Scrubs is one of the most well-received comedy television series of all time. For all the snappy dialogue, emotional moments, and hilarious episodes, our favorite aspect was the characters. These were fully fleshed out and flawed people who we cared deeply about. And that feeling didn't only apply to the main cast.

Guest stars came around Sacred Heart Hospital all the time. Some of the most talented actors in film and television were among them. Though we could fill up multiple lists of the best guest stars in Scrubs history, we've narrowed it down to the top ten.

Matthew Perry

Murray Marks standing next to his father in Scrubs

Matthew Perry appeared in the episode "My Unicorn" as Murray, the son of a patient of JD's. His father, Gregory, needed a kidney transplant, but Murray declined because his dad wasn't around for him when he was growing up. Also, he was upset that he was given an "old man's name."

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Eventually, Murray found out that Gregory wasn't his biological father. He still ultimately gave him his kidney because he was at least a decent father. Matthew Perry didn't stop at just giving a strong performance as an actor. He also got behind the camera and directed this episode. Another cool tidbit: Perry's real father portrayed Gregory in this episode.

Tara Reid

A trend you'll notice on this list is that a lot of these guest stars played girlfriends or hookups of series protagonist JD. That was the case with Tara Reid, who portrayed Danni Sullivan in 11 episodes. The relationship between JD and Danni was interesting for a handful of reasons.

For one, both JD and Danni had inner monologues going on at all times. Another wrinkle in their courtship was that Danni was the sister of Jordan, a past hookup of JD. Danni was also the sister-in-law of Dr. Cox, meaning that JD was around the family way more often than Dr. Cox wanted, leading to hilarious situations.

Mandy Moore

You know her from the smash hit This Is Us, but long before her role as Rebecca Pearson, Mandy Moore had a guest-starring role on Scrubs. She played Julie Quinn, the new girlfriend of JD. It was a role that lasted only two episodes during season four, but it was memorable.

There's a great montage of the happy couple set to "Hey Julie" by Fountains of Wayne. What helped make this work was Mandy Moore's natural chemistry with Zach Braff as the two were dating during the time of filming. JD ruined the relationship by nitpicking the fact that Julie always said, "That's so funny," instead of laughing when something comical happened.

Heather Graham

Season four was a great time for guest stars. Heather Graham had a nine-episode run during that stretch as Dr. Molly Clock. She was the staff psychiatrist and had some great interactions with most of the main characters. She fit in so seamlessly with the rest of the Sacred Heart family.

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Molly ended up as a friend to Elliot, love interest to JD, and a foil for Dr. Cox. She was pretty much the only person in the hospital immune to Dr. Cox's verbal jabs. It was interesting to watch Graham play a character who held so many roles during her time on the show.

Ryan Reynolds

When Ryan Reynolds appeared on Scrubs in the season two episode, "My Dream Job," he was still years away from being the box office star of Deadpool. He was showing off his comedic chops as Spence, a college friend of both JD and Turk who comes to visit them. It was only for one episode, but it was a doozy.

Ryan Reynolds fit into the funny world of the show so seamlessly that he could've become a series regular and nobody would've batted an eye. Spence wasn't just a fun guest, either. While out with the crew, he drunkenly revealed to Dr. Cox that he was the father of Jordan's baby.

Amy Smart

Now we've reached Ryan Reynolds' Just Friends co-star, Amy Smart. She appeared in a handful of season two episodes as Jamie Meyer, but was better known as "Tasty Coma Wife." Jamie's husband had been in the hospital for an extended stay while in a coma, and the nickname was something JD and his buddies came up with.

Jamie and JD flirted with each other, but JD was torn because her husband wasn't technically gone. Once he passed away and their relationship was real, JD found out that Jamie was only interested when there was drama. Smart has strong comedic timing and it showed during this stint.

Tom Cavanagh

Scrubs was dynamite at casting stars who would go on to do big things. Tom Cavanagh has been killing it over on The Flash since that show began airing. Here, he played JD's brother Dan for seven episodes sprinkled throughout the course of the series. Casting Cavanagh was a stroke of genius.

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Tom was a good choice because he bore a striking resemblance to JD and they played well off each other. Not only that, but their storylines together were always meaningful. There was Dan realizing that JD no longer idolized him, JD dealing with Dan dating Elliot, and when both handled their father's passing.

Michael J. Fox

Michael J. Fox starred as Dr. Kevin Casey in two episodes during season three. It was one of the dramatic roles for a Scrubs guest star. Casey was a stellar doctor but he suffered from obsessive-compulsive disorder. The condition was given to the character to help mirror Fox's real struggle with Parkinson's disease.

The scene where Casey is confronted by JD and has an emotional outburst about his condition remains one of the most emotional moments in series history. Thankfully, Fox also had some great comedic bits to work with as he continually bested Dr. Cox in a battle of medical knowledge in a nonchalant manner.

John Ritter

The late, great John Ritter was a spot-on casting choice to play JD and Dan's father, Sam Dorian. Appearing in the first two seasons, Ritter was a blast. Sam wasn't the most mature father, opting to try and be one of the guys. He seemingly has a stronger bond with Turk than he does with JD.

Sadly, John Ritter wasn't able to be in many more episodes. His untimely passing in 2003 led Scrubs to write it into the show, allowing JD and Dan to deal with these emotions. Since Scrubs was a show that handled this kind of thing with great care, it was used as a way to say a proper goodbye and pay tribute to the legendary actor.

Brendan Fraser

Brendan Fraser Scrubs

Following his success with The Mummy franchise, it was nice to see Brendan Fraser show off his comedy skills again. He portrayed Ben Sullivan, best friend of Dr. Cox, and brother to Jordan and Danni. Appearing in three episodes spanning a few seasons, Fraser was perfect. He was every bit as ridiculous as JD and Turk, while also somehow being a great fit as Dr. Cox's buddy.

Though Ben was one of the funniest characters on the show, he's most remembered for his heartbreaking cancer storyline. He took the sickness in stride and still had fun in every appearance. Fraser played the character with glee and was dynamite in every scene. Ben's death was arguably the saddest moment in Scrubs history.

NEXT: Scrubs: 10 Saddest Moments, Ranked