Sitcom co-stars have to relate to each other on screen, as well as off screen. They have to manage the on-screen relationships they portray in tandem with off-screen relationships that could be friendly, ambivalent, or downright hostile. While on-screen relationships sometimes mirror real life, co-stars often have to deal with the fact that on-screen and off-screen relationships aren't always the same.

Thus, stars often struggle to put up with the discomfort of smiling, giggling, hugging, and even kissing a co-star with whom they don't get along once the cameras stop rolling. The extreme inconvenience of such a situation explains why directors always wish that co-stars who have to be friends on screen would, at least, be able to tolerate each other off screen.

However, human relationships are usually more complex than the simplifying absolute duality of hate or love. In most cases, real-life relationships consist of a mix of contradictory feelings of love and hate. The fact that love-hate relationships tend to portray reality better than exclusively love or exclusively hate relationships could explain why more and more TV shows are portraying characters who are frenemies.

In the light of the preceding, we present 8 Sitcom Co-Stars Who Are Best Friends (And 7 Who Are Frenemies).

Best Friends: Elizabeth Gillies & Victoria Justice (Victorious)

Elizabeth Gillies' character, Jade West, and Victoria Justice's character, Tori Vega, were frenemies in the Nickelodeon sitcom Victorious (2010-2013), but the girls were best friends in real life. Their off-screen friendship continued after the end of the show in 2013. The two posted selfies to Twitter in August 2016 that, once again, drew the attention of fans to their enduring friendship.

Justice tweeted a selfie of her and Gillies taken during a meet up with a group of friends on the night of August 9th, 2016. Justice told Teen Vogue she and Gillies had met at the Television Critics Association Awards where Justice was promoting her upcoming movie, Rocky Horror Picture Show: Let's Do The Time Warp Once Again (2016).

Fans were delighted to see Justice and Gillies together again after speculation erupted about their relationship, when it was noticed that they did not attend co-star Ariana Grande's birthday party the previous June. Fans were also pleased to see that the two had sustained their friendship and remained close three years after they co-starred on Dan Schneider's Victorious.

Elizabeth Gillies and Victoria Justice also had a reunion with former Victorious co-stars Matt Bennett and Leon Thomas in September 2015. Victoria shared photos of the reunion on her Instagram page.

Frenemies: Charlie Sheen vs. Selma Blair (Anger Management)

Charlie-Sheen-Selma-Blair-Anger-Management

Charlie Sheen and Selma Blair had a close relationship, but they reportedly failed to get along on the set of the FX sitcom Anger Management (2012-2014). Sheen reportedly fired Blair in 2013 through an angry text message. Blair then accused Sheen of firing her because she complained about his conduct, and threatened to sue.

Some sources claimed that Blair had complained about Sheen to the producers, but other media sources insisted that Sheen fired Blair because she complained about his poor work ethic to people who were not part of the show. She reportedly complained that Sheen always came late for rehearsals and that cast members were bothered about his poor work ethic. Sheen felt offended when he learned that Blair was complaining about him.

Sources indicated that Sheen's decision to fire Blair was the culmination of a long and complicated relationship.

Sheen had reportedly admired Blair's performance in the movie Cruel Intentions (1999) and got someone to introduce them. He also felt attracted to her and they developed a close relationship, according to sources. He asked her to join the cast of Anger Management, but their relationship soured after Sheen learned that Blair was criticizing him behind his back.

Best Friends: B.J. Novak & Mindy Kaling (The Office/The Mindy Project)

B.J. Novak and Mindy Kaling met when they were hired as writers and cast members in the mockumentary sitcom The Office (2005-2013). The two Boston-area natives grew very close while filming the sitcom and their relationship remains strong today, many years after the show ended. The details of their off-screen relationship are well known to fans of The Office and The Mindy Project (2012-2017). The have proved inseparable despite several relationship ups and downs.

They started dating after they met on the set of The Office at a time that their on-screen characters, Ryan Howard and Kelly Kapoor, were also romantically involved. Novak revealed in an interview with Vulture that The Office plotline in which Ryan and Kelly became romantically involved was inspired when the writers noticed that the actors had a close off-screen relationship, although they sometimes quarreled.

The pair remained close after their romantic relationship ended. Kaling left The Office in 2012 to focus on her show, The Mindy Project. Novak later made guest appearances in four episodes of The Mindy Project (2012-2017) as Mindy Lahiri's friend and love interest, Jamie.

Their friendship has survived over the years and they continue to demonstrate mutual affection on Twitter, with Novak posting a tribute to Kaling in March 2018 to celebrate her role in the movie A Wrinkle in Time (2018).

Frenemies: Sarah Jessica Parker vs. Kim Cattrall (Sex And The City)

Although Carrie Bradshaw and Samantha Jones had a great on screen chemistry, it was rumored for years that Sarah Jessica Parker and Kim Cattrall, who played the characters in HBO's Sex and the City (1998 - 2004), did not get along. The bad blood between the co-stars made them ignore each other when they weren't filming scenes for the show.

Some tabloids blamed Cattrall for the decision to shelve Sex and the City 3. Others claimed that, while she promoted a "nice girl" image in public, Parker fostered an onset cliquishness that ostracized Cattrall. Yet, other sources traced the origin of the feud to the time Cattrall learned that Parker was earning more than she was.

After Parker confirmed rumors in September 2017 that Sex and the City 3 had been shelved, she expressed regret about it. However, in an interview with Piers Morgan, Cattrall denied the rumors that Sex and the City 3 was shelved because she demanded to be paid more. She said she made the decision, since 2016, that she did not want to be involved in any more sequels and admitted that she and Parker had never been friends.

When Parker offered her condolences on Instagram following news of the passing of Cattrall's brother in February 2018, Cattrall responded, saying she did not need Parker's love or support. She called her former co-star a cruel and hypocritical person, and accused her of trying to use the tragedy to promote her "nice girl" persona.

 11. Best Friends: Jennifer Aniston & Courteney Cox (Friends)

The relationship between Jennifer Aniston and Courteney Cox started in 1994, when they met on the set of the popular NBC sitcom Friends (1994-2004). Aniston played Rachel Green while Cox played her best friend, Monica Geller.

Rachel and Monica have been described as one of the greatest fictional friendships ever, and Aniston and Cox have remained dedicated friends since the show ended in 2004.

Aniston revealed in a 2014 interview with More magazine that Cox was there for her when she went through a painful divorce from Brad Pitt in 2005. She expressed gratitude to Cox that she was willing to accommodate her when she needed a place to stay. She added that Cox was extremely fair, loyal, and loving -- attributes good friends should all have.

In February 2018, Aniston celebrated her 49th birthday with Cox and a couple of friends in Malibu, according to People magazine. She marked her birthday with a lunch outing with Cox, Andrea Bendewald, Kristin Hahn, and Leigh Kilton-Smith, and posted photos of the occasion to Instagram.

Aniston's celebration of her 49th birthday was low-key compared with the previous year, when she vacationed with her husband Justin Theroux and Cox in Los Cabos, Mexico.

Frenemies: Ariana Grande vs. Victoria Justice (Victorious)

Ariana Grande and Victoria Justice met in 2010 on the set of the Nickelodeon sitcom Victorious (2010-2013) and struck up a friendship. They were best friends while they co-starred as Cat Valentine (Ariana Grande) and Tori Vega (Victoria Justice) in Victorious. However, they had a falling out after it was announced in February 2013 that the show would be canceled.

Fans of the show blamed Grande for the cancellation of Victorious and alleged that it was due to Grande's involvement in a spin-off series, Sam & Cat (2013-2014). According to disappointed fans, the show was canceled because Grande wanted to focus on other projects, including her solo music career. Grande denied the allegations and insisted that the cancellation had nothing to do with her.

She blamed Justice on social media, saying that it was Justice's decision to go on a solo tour, instead of a cast tour, that sealed the fate of the show. According to Grande, if Justice had done a cast tour, Nickelodeon would have renewed the show for another season.

Justice responded to Grande's comment on Twitter with the hashtag #StopBeingAPhony, and described her comments as misinformation. According to Justice, her actions did not influence the decision to end the show. Later in an interview with TMZ, Justice tried to downplay rumors of a feud between her and Grande. She said she wished Grande well and that she was happy for her.

Best Friends: Kelly Cuoco & Amy Davidson (8 Simple Rules)

Kaley Cuoco and Amy Davidson met in 2002, when they were cast as sisters in the ABC sitcom 8 Simple Rules and have been best friends since. They also kept in touch with 8 Simple Rules co-star Martin Spanjers, who played Rory Hennessy, Bridget and Kerry’s brother.

Cuoco, Davidson, Spanjers, and other members of the cast of 8 Simple Rules, often have reunions during which they remember some of their former co-stars, including John Ritter, who played Paul Hennessy in the show, but passed away in 2003. James Garner, who replaced Ritter as Paul Hennessy, also passed away in 2014 at the age of 86.

Media reports have documented Davidson and Cuoco's friendship over the years. A photo emerged on social media in July 2016 showing Cuoco beaming happily as she cuddled Davidson’s four-month-old baby boy Lennox, after they had lunch together at Granville Cafe in Studio City, L.A. The photo was taken soon after Cuoco finalized her divorce from tennis pro Ryan Sweeting in May 2016.

She began dating Karl Cook, son of the billionaire Intuit software co-founder Scott Cook. Davidson gave her blessing to the Cuoco's relationship with Cook in an interview with Entertainment Tonight.

Frenemies: Bea Arthur & Betty White (Golden Girls)

Bea Arthur and Betty White in Golden Girls

Despite the fact that Bea Arthur and Betty White's characters -- Dorothy Zbornak and Rose Nylund -- in the NBC sitcom Golden Girls (1985-1992) did not always get along, they were overall good friends on the show and had a remarkable on screen chemistry. However, many fans found it hard to believe that they weren't also best friends in real life and that they had a tense off-screen relationship.

The fact that the two had an off-screen feud emerged in multiple interviews years after the show ended. White revealed to Country Living that there were serious issues between them during the time they co-starred in Golden Girls, although they had started off as best friends and lived near each other for some years. In an interview with Village Voice in 2011, White also admitted that Arthur was not fond of her and that they were not best friends off screen, which many people had believed to be true in the past.

It was rumored that the tension between the pair was due to Arthur’s jealousy when White was nominated for an Emmy before she was.

Eventually, all the Golden Girls won Emmys. However, White was the first to win the Award for Outstanding Lead Actress in a comedy series in 1986.

Best Friends: Donald Faison & Zach Braff (Scrubs)

Donald Faison and Zach Braff, former co-stars in the NBC sitcom Scrubs (2001-2010), first met on the set of the show in 2001 and immediately hit it off with each other. Their characters in Scrubs, Chris Turk (Faison) and John Dorian (Braff), had one of the most famous on-screen friendships ever. What made Turk and J.D.'s onscreen relationship even more remarkable was that the actors who portrayed the characters had a similar off screen relationship.

Faison and Braff's friendship is often jokingly referred to as Hollywood’s ultimate bromance.

The two have been open about the fact that they are very fond of each other, and they do not hesitate to flaunt their mutual affection publicly.

The often exchange greetings and playful banter on social media, and document their vacations together.

Once, when asked to explain the secret behind their friendship, Faison told Yahoo! that there was no secret besides the fact that they were so fond of each other that not even his marriage to CaCee Cobb was able to get in the way of their friendship. According to Faison, Cobb knew what she was getting into when she decided to marry him and she has helped to keep his friendship with Braff going.

Braff celebrated his 31st birthday with Faison in 2016 at the Cape Hotel in Cabo San Lucas. They documented the event with photos and comments on their Instagram pages. One Instagram photo showed Faison carrying Braff inside a pool.

Frenemies: Will Smith vs. Janet Hubert (The Fresh Prince)

The Fresh Prince of Bel-Air (1990-1996) co-stars, Will Smith and Janet Hubert -- who played Aunt Vivian -- were originally friends, but their relationship soured after they clashed repeatedly on the set of the popular sitcom. Hubert was eventually fired from the show in 1993 and replaced by Daphne Maxwell Reid. Hubert accused Smith of getting her fired from the show and has been feuding publicly with him since then.

After Smith and his wife, Jada Pinkett-Smith, announced that they were boycotting the 2016 Academy Awards ceremony to protest lack of diversity in the nominations, Hubert uploaded a video to Facebook in which she accused the couple of vanity and insincerity. She alleged in the video, which went viral on Facebook, that the Smiths decided to boycott the Oscars not because they wanted to stand up for minorities, but because they were disappointed that Will did not receive a nomination for his role as Doctor Bennet Omalu in the movie Concussion (2015).

Hubert also recalled an incident in which she and other Fresh Prince cast members asked for Smith’s support when they were fighting for a salary increase. Smith, according to Hubert, refused to support them. She claimed that it was the bad blood from that incident that caused Smith to get her fired from the show in 1993, after only three seasons.

However, Smith responded to Hubert’s accusations in a radio interview, saying that she had wanted the show to be "The Aunt Viv of Bel-Air Show."

Best Friends: Selena Gomez & David Henrie (Wizards of Waverly Place)

Selena Gomez and David Henrie have been very close friends since they co-starred as siblings Alex (Gomez) and Justin (Henrie) Russo in the Disney Channel sitcom Wizards of Waverly Place (2007-2012). Alex and Justin were typical siblings who often quarreled, but they loved each other and were fiercely protective of each other.

Gomez and Henrie's off-screen friendship continued after the show ended in 2012. Their closeness sparked rumors of romantic involvement. Gossip tabloids speculated about their relationship when they were seen together on a dinner date in November 2014, soon after Gomez's heartbreaking split from Justin Bieber. However, sources close to the two insisted that they were only friends. The rumors and speculation flared up once again when the two were seen together again on a dinner date in 2015 in Calabasas, California.

Henrie eventually married former Miss Delaware Maria Cahill on April 20, 2017. Gomez and several other members of the cast of Wizards of Waverly Place attended the wedding. After tying the knot with Cahill, David gushed that he was very happy to have married Cahill because it was always best to marry one's best friend.

Many fans thought that David should have married Gomez if he had really wanted to marry his best friend.

However, Henrie told People magazine that Gomez was the first person he informed when he and Cahill decided to get engaged.

Frenemies: Kirk Cameron vs. Julie McCullough (Growing Pains)

Trouble erupted between Kirk Cameron and Julie McCullough, co-stars in the ABC sitcom Growing Pains (1985-1992), after Cameron, formerly an atheist, converted to evangelical Christianity. Cameron's religious sensibilities were reportedly offended when he learned that McCullough, who landed the role of his fiancée in the show in 1989, had previously featured in the centerfold of a magazine.

Kirk was allegedly concerned that McCullough's role as his girlfriend would hurt his image as a born-again Christian. However, in his 2008 autobiography, Still Growing, Cameron denied allegations that he got McCullough fired, but media reports claimed Cameron's conversion alienated him from his cast mates. For instance, when he married Growing Pains co-star Chelsea Noble in July 1991, he did not invite his castmates to his wedding. He also did not maintain contact with them after the show was canceled because he wanted to focus on his personal life.

The cast had three reunions in the 1990s, at the weddings of Alan Thicke, Joanna Kerns, and Tracey Gold, according to Los Angels Times, but Cameron did not attend any of the weddings. He later claimed that he did not attend the weddings because he was not invited.

When the cast reunited in 2000 for the Growing Pains movie, Cameron expressed regret about how his conversion affected his relationship with his castmates, saying that if he could go back he would do things differently.

Best Friends: Olivia Holt & Austin North (I Didn't Do It)

Olivia Holt and Austin North co-starred on the Disney Channel sitcom I Didn't Do It (2014-2015). Olivia played the role of Lindy Watson, the twin sister of Austin's character, Logan. Lindy and Logan's on-screen sibling relationship was very close. Olivia and Austin also had an off-screen friendship that predated their roles as twins in the Disney Channel sitcom.

Olivia told MTV News that she and Austin were just like twins in real life before they played twins in I Didn’t Do It. According to Olivia, she and Austin were weirded out when they both landed the roles of twin characters in the show because they already had a "little twin thing going on in real life" for some years.

They had known each other and had been best friends since they were 13 years old.

Their off-screen relationship mirrored the relationship of their characters in the Disney show. Austin and Olivia had also played roles in Disney's Kickin' It (2011- 2015) before they were cast as twins in I Didn’t Do it. Austin played the role of pop sensation Ricky Weaver in Kickin’ It, and Olivia's character Kim Crawford had a crush on Ricky.

Olivia and Austin follow each other on Twitter and often display their mutual affection through their social media posts.

Frenemies: Lindsay Lohan vs. America Ferrera (Ugly Betty)

America Ferrera and Lindsey Lohan Ugly Betty

America Ferrera and Lindsay Lohan fell out in 2008, after Lohan appeared as a guest star in only four episodes of Ferrera's ABC sitcom Ugly Betty (2006-010). Lindsay appeared as Kimmie Keegan, a former high school classmate of Ferrera's character, Betty Suarez. E! reported that Ferrera asked for Lohan's character to be written out of her show after only four episodes, instead of the scheduled six, because she found Lohan very difficult to work with.

Lohan reportedly clashed with Ferrera, who was the show star. According to media reports, Lindsay usually showed up for filming with an unwieldy entourage, including her sober companion, her manager, an assistant, her publicist, and a girlfriend.

During the filming of an episode of the sitcom titled "Granny Pants," Lohan's character was supposed to pull down Ferrera's pants. However, Ferrera’s character outwitted Lohan's and pulled down Lohan's pants instead. Lohan was reportedly embarrassed and began crying.

An unnamed source close to Lohan insisted that it was only a rehearsal and that Ferrera wasn't supposed to actually pull down Lohan's pants. Needless to say, it is unlikely these two will be working together anytime soon.

Best Friends: Seth Rogen & James Franco (Freaks and Geeks)

Seth Rogen and James Franco in The Interview

Seth Rogen and James Franco met in 1999 on the set of the NBC sitcom Freaks and Geeks (1999-2000) and started a friendship that lasted nearly two decades. Seth Rogen revealed in an article published on Indie Wire in November 2017 that, when he and James Franco first met in 1999, there was nothing in the circumstances of their first acquaintance that suggested they would later go on to build such a close professional and personal relationship.

After Freaks and Geeks was canceled in 2000, they parted ways and did not see each other for some years although they maintained contact. Franco's first major achievement after Freaks and Geeks ended was portraying the title character in the TV biographical movie James Dean (2001). Rogen admitted that he did not like Franco in the role and that he tried to dissuade him, but Franco won a Golden Globe Award for his role in the TV movie.

When Rogen and Evan Goldberg wrote Pineapple Express in 2007, they invited Franco to star in the movie released in 2008. Rogen and Franco went on to collaborate in several other movies, including Knocked Up (2007), The Green Hornet (2011), This Is The End (2013), The Sound and Fury (2014), The Interview (2014), Zeroville (2015), Sausage Party (2016), and The Disaster Artist (2017).

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Did we miss any sitcom co-stars who are friends or frenemies? Share with us in the comments section.