After an incredibly successful ten-year run, Friends came to an end in 2004 and to this day, remains one of the most successful sitcoms of all time. In the eyes of fans, the character arcs and storylines have remained timeless and it seems unlikely that the show’s popularity will ever die out, with fans re-visiting it and new generations discovering the vivid and relatable characters.

RELATED: The Worst Character In Each Season Of Friends

Aside from the beloved main six, the 10 seasons of Friends introduced countless characters that the audience will always remember. Despite there being 236 episodes in total, these famous faces only needed one episode to leave their mark on fans.

Updated Feb 7th by Meg Schimelpfenig: Friends was essentially a revolving door for compelling characters to come in and shake up the lives of the six stars, and it seems like every major celebrity at the time was knocking at NBC's door for a chance to come on the show. However, after ten seasons and countless creative storylines, some of the personalities stood out the most.

Ryan, "The One With The Chicken Pox"

Charlie Sheen played Phoebe's ex-boyfriend, the Lieutenant Commander who comes to Manhattan only to discover Phoebe is covered in chicken pox. Ryan ends up catching it too, and the audience watches his relationship with Phoebe unfold through lots of scratching.

Sheen's notoriety at the time makes his appearance a standout, and this episode premiered at the height of his Two and A Half Men fame. The bit with the oven mitts is genius, and Sheen brings a masterful combination of comedic timing and charisma to the character. The writers left room for this character to be brought back, and if they had included Ryan in a later season he would have been even higher on the list. Still, lightning struck with this episode, both literally and figuratively.

Dr. Michael Mitchell, "The One With Two Parts: Part 2"

Friends George Clooney Noah Wyle

In a tribute to ER, George Clooney appeared in the first season alongside co-star Noah Wyle as two handsome TV doctors that both got set up on dates with Monica and Rachel.

Related: 10 Things From Season 1 Of Friends That Get Better Over Time

Clooney and Wyles' appearance could have been pure network cross-promotion, but it worked. They were an event themselves, and Clooney's continued relevancy makes it all the more memorable. It's was a real winner of an episode at the time, but it's even more fun to look back on in retrospect, given that when this was shot in front of a live audience, neither Clooney nor Friends itself knew just how famous they would become in the television world and far beyond.

Zach, "The One With The Donor"

John Stamos portrays Chandler's classically good-looking, quite normal coworker who is unwittingly interviewed as a potential sperm donor for him and Monica.

A definite highlight of season nine, the Full House actor's dinner table line of questioning was pretty amazing, as was the choice to have Zack requesting a coaster for his beer be the thing that changes Monica's mind. He's a significant character too, just for the trajectory of Monica and Chandler's relationship after she decides it's Chandler's sperm or no one's. Zach's impact on that couple, combined with the clever writing of his character arc makes him great.

Eric, "The One With The Halloween Party"

Sean Penn as Eric on Friends

Nobody can forget Sean Penn's solar system Halloween costume. The fiancé of Ursula, Phoebe accidentally falls for Eric too, and with both twins going after the second grade teacher at the same time, chaos ensues.

Eric's character is more likable than many of the other more "kooky" guest stars, and it has the power to get the audience to root for him and Phoebe, despite the unconventional nature of their relationship. Penn is known primarily for his dramatic acting work and serious directing and producing, so it was a real treat to see him take on such a fun, comedic role in front of a live audience. The entrance when he mistakes Phoebe for Ursula is remembered as one of the finest in the Friends fanbase.

Melissa Warburton, "The One With Rachel's Big Kiss"

Winona Ryder plays old sorority sister to Rachel, and her character Melissa's iconic episode surrounds a kiss the two women may or may not have shared in college.

Fun fact: Ryder herself is actually mentioned in a previous episode on a list of celebrities Ross is allowed to hook up with while dating Rachel. The full-circle nature of this, combined with the earnest nature of her character, and Winona Ryder's pure presence in celebrity culture at the time makes this guest appearance a tried-and-true fan favorite. Plus, there's an added will-they-kiss-again element, which makes for a satisfying ending.

Amanda Buffamonteezi - "The One With Ross' Tan" (S10, E3)

Monica, Amanda and Phoebe all sit in the coffee house

Played by Jennifer Coolidge, Amanda is a self-centered and ignorant woman who used to live in Monica's building. When Phoebe reveals that Amanda is back in town, she and Monica try and cut her out – with no luck.

Amanda’s presence causes people to question Monica and Phoebe’s friendship, however, there’s no denying that her one-liners and eccentric dances are amusing. Amanda allowed Monica and Phoebe’s earlier lives to be explored and although she has few redeeming qualities, she was hilarious to watch and a great addition to the episode.

Erika Ford - "The One After The Superbowl, Part 1" (S2, E12)

Erika and Joey on a date in Friends

In "The One After the Superbowl: Part 1," Erika was introduced as an eccentric superfan of Dr. Drake Ramoray. Despite everyone recognizing that she was crazy, Joey still went on a date with her where she displayed plenty of strange behavior (like intensely licking his hand).

Brooke Shields' take on the intense character was one to remember because it took a lot to find a woman that Joey needed to avoid. While her appearance was her main attraction for Joey, she showed that beauty isn’t everything and Joey was right to swerve her.

The Guy On The Plane - "The One With Ross' Wedding, Part 2" (S4, E24)

Friends Hugh Laurie

No plane journey on Friends is uneventful and thanks to the guy who sat next to Rachel, her flight to London was made even more notable. On her way to Ross' wedding, Rachel rants to another passenger about their history. When the guy overhears, he doesn't hold back and tells Rachel that she is a horrible person.

RELATED: 10 Most Unexpected Things That Happened In Friends

Despite only featuring for a few minutes in total, the guy's reactions to Rachel’s stories are highly comical. While Rachel expects sympathy, he gives her the complete opposite, leaving his honest and blunt character engraved in fans' minds.

Cecilia Monroe - "The One With Joey's New Brain" (S7, E15)

Cecilia Monroe holding Joey's face on Friends

Cecilia was an actress on the fictional Days of Our Lives and was a brilliant supporting character in "The One with Joey’s New Brain." Needing help on how to play her character, Joey asks Cecilia for advice and the two eventually sleep together. Unfortunately, their relationship is short-lived when Cecilia lands a new job in Mexico.

Although it’s unlikely that their relationship would’ve gone any further had she not moved away, it was interesting to watch Joey interact with a woman he considered more than a one-night stand. Susan Sarandon captured Cecilia's feisty side perfectly and it was unfortunate her character didn’t get more screen time.

Sandy - "The One With The Male Nanny" (S9, E6)

Sandy the Nanny talks to a crying Ross in Friends

The 200th episode of Friends saw the introduction of Sandy, a male nanny. Ross instantly has trouble coming to terms with his profession – one of the many things that have aged poorly about Ross. Ross' feelings towards Sandy eventually lead to him being fired, but not before Sandy gets Ross to open up.

Despite the tough reception from Ross, Sandy remained enthusiastic and proved to be excellent at his job. It was interesting to watch a male character defy gender stereotypes, and his brief appearance was a great way to establish that there is no need to stay within expected gender roles.

Earl - "The One Where Rosita Dies" (S7, E13)

Jason Alexander as Earl with Phoebe on Friends

In "The One Where Rosita Dies," Phoebe’s new job selling toner means her life intertwines with the troubled supply manager, Earl. When Earl tells Phoebe that he is going to take his own life, Phoebe rushes to his office to convince him that life is worth living.

This provided fans with a unique and touching storyline and although he was never mentioned again, it's assumed that Phoebe was successful in stopping him. Seinfield actor Jason Alexander played the role of Earl with great thought and depth and his character will always be remembered.

Tommy - "The One With The Screamer" (S3, E22)

Tommy outside Central Perk on Friends

Tommy was introduced in season 3 as a brief and unlikeable boyfriend of Rachel's. Behind closed doors he had severe anger problems, however, he managed to disguise it well in the presence of others. At the end of the episode, Rachel dumped him after watching him unleash his rage on a duck.

Tommy was played hilariously by Ben Stiller and while Friends saw many romantic partners come and go, he was one of the most memorable. Although he merely acted as a steppingstone in Rachel’s attempt to get over her breakup with Ross, he proved to be a great addition because he was like nothing anyone had ever seen before.

Tomas - "The One With The Ultimate Fighting Champion" (S3, E24)

Tomas and Tim in Central Perk on Friends

In "The One with the Ultimate Fighting Champion," Tomas and Tim enter the coffee house where the gang overhears their conversation. Tomas expresses his worry to Tim that his wife is cheating on him. The drama begins to unfold when Tim reveals he's the one who's been sleeping with his wife.

RELATED: 10 Most Iconic Quotes From Friends

Tomas' appearance was extremely brief and, as they were never seen or mentioned again, fans have no idea whether Tomas and Tim’s friendship survived. Although a longer appearance would’ve gone down a treat, the late Robin Williams' cameo was short and sweet and one of the funniest in the show’s history.

Will Colbert - "The One With The Rumor" (S8, E9)

Will looking angry while talking to Ross in Friends

"The One with the Rumor" is the funniest episode of Friends season 8 and is simply unforgettable. This is all thanks to Will, Ross' high school friend who had an unresolved and deep hatred for Rachel. Will's presence brings up old high school memories and rumors that make this Thanksgiving dinner a brilliant watch.

Rachel was never shy of male attention, therefore Will made for an interesting character with an unseen opinion on her. As Jennifer Aniston’s husband at the time, it was also a nice touch for Brat Pitt to play a character with a relationship to Rachel that was the complete opposite of their real-life romance.

"Officer" Roy "Goodbody" - "The One Where The Stripper Cries" (S10, E11)

Danny DeVito as the Stripper on Friends standing next to Phoebe

Phoebe’s bachelorette party introduces Officer Goodbody, a middle-aged stripper played by Danny DeVito. When he starts his routine, he receives squirmish looks from the guests that make him think it’s time to quit his beloved profession. But not before Phoebe asks him to perform one last time out of pity.

When thinking of a stereotypical stripper, it's not unfair to say that Danny DeVito wouldn’t be the first thought that comes to mind. Despite this, fans were delighted when he popped up in this unmatched cameo. He played Officer Goodbody with priceless hilarity and his character will always be remembered as iconic.

NEXT: 10 Friends Side Characters With Main Character Energy