Before becoming an Avenger, Paul Rudd was better known as Phoebe’s love interest Mike Hannigan. The lovable, charming, and handsome actor starred in 18 episodes of Friends thanks to how much the audiences wanted to see him. Given Phoebe and Mike’s on-screen chemistry, it was only fitting that the two married in the last season.

While Rudd may have been one of the important guest stars for the story arc, however, he didn’t feel all that important on set.

On Variety’s Actors on Actors, he revealed to Chris Evans that the show was about the main characters and he felt like a prop. He said, “In something like Friends, the show was about them. I was only in it for just a blip”. Although he felt cast aside, he played Mike’s character perfectly and fans were definitely stoked to see him perform. Reportedly, he had only signed a contract for two episodes, but the writers kept developing his character.

The Dead to Me star plays an obnoxious sister to the hilt. As Rachel’s sister Amy, she causes a lot of problems when she pierces Emma’s ears without Ross and Rachel’s consent. Applegate’s brief stint on the show brought several funny instances, including the impromptu dialogue “Why does she keep making that noise?!” Amy can’t, for the life of her, remember Phoebe’s name and keeps calling her Emma, while also puzzling over why continues Phoebe to say “Phoebe” as a response.

In an interview with Today, Applegate said that the line was a rewrite that happened in front of the studio audience. Now, we can’t imagine an episode in which this joke doesn’t feature. Christina Applegate’s amazing performance as Amy won her an Emmy for Outstanding Guest Actress in a Comedy. She was simply shocked to even get nominated because she was simply having so much fun and never knew the cameo would be so hilarious.

Hollywood’s treasure shows up as Leonard Hayes, a famous actor who appeared in a monkey commercial. He gives Joey a confusing pep talk on acting, but Joey managed to nail his audition only because he had to pee really bad. He ends the scene as soon as he can to rushes toward the bathroom. Hayes stops him to give a congratulatory hug, but poor Joey can’t hold it for any longer and “relaxes” as also suggested by Hayes. Goldblum brings the charisma and adds to the hilarity with his serious acting chops.

Before appearing on the show in 2003, Jeff Goldblum had starred in box office hits like Jurassic Park, Independence Day, and their sequels, which is why the audience was cheering like crazy when he appeared on the show. After his time on Friends, he was seen in other major TV productions like War Stories and Law & Order: Criminal Intent.

Sean Penn played Ursulas’s fiance Eric and first appears in season 8 at a Halloween Party. Later on in the series, he and Phoebe even try dating, but it’s weird since he can’t look at Phoebe without being reminded about Ursula. Sean Penn played Eric on two subsequent episodes in 2001 and fans are somewhat unanimous on his charming portrayal of the klutz-like Eric.

According to The Sun, Sean Penn and his family were fans of the sitcom, and they made many trips to the set. The co-creator of Friends David Crane said that he liked Penn’s comedy and was confident that he would fit Eric’s role well. Entertainment Weekly mentioned that the producers of the show only pitched Eric’s role to Penn after they had created the perfect character. Well, we’re not surprised. We’re talking about Sean Penn here, Oscar winner for Dead Man Walking!

Gary Oldman plays veteran actor Richard Crosby, who has a major drinking problem and spits while enunciating his dialogues. Joey needs to finish a vital scene with Crosby to make it on time to officiate Chandler and Monica’s wedding. Oldman is fun to watch because he portrays the character’s quirks so well. And then there's Joey...just something about Joey meeting these veteran Hollywood actors and choosing to simply be himself. Remember his rapport with Goldblum? Well, that’s just a Joey-thing we suppose. Oldman and Matt LeBlanc’s on-screen comradery could also have come from their previous work together in the 1998 sci-fi classic Lost in Space. Before Gary Oldman appeared on Friendsin 2001, he had attained star quality starring in amazing movies like The Fifth Element and Air Force One. Gary Oldman is still doing well in the industry, given that he bagged the role of Sirius Black in the Harry Potter film series, and more recently, played the role of Herman J. Mankiewicz in the Netflix film Mank.

She plays Cecilia Monroe, who acts alongside Joey on Days of our Lives. After her character Jessica Lockhart gets killed off the show, her brain is “transplanted” into Joey’s head and she lives on through him. She eventually takes a job in Guadalajara that Joey hilariously confuses with LaGuardia. We see Sarandon only once in the show, but she makes quite an impression with her acting. She has said that it was great working with Matt LeBlanc and that she would like to work with him again.

While talking with US Weekly, Sarandonsaid that she insisted the producers give her a big wig, reasoning that a character working in a soap opera would have “good, big hair.” After they had explained the role to her, and her demand for the big hair was accepted, there was nothing holding her back from accepting the role. Fun fact: Susan's real-life daughter, Eva Amurri, appears in the same episode as Celia's character's daughter.

In season 4, we saw the one and only Charlton Heston star as himself. Joey uses the shower in the legend’s dressing room and he...well…gives Joey a dressing down. But Heston was also gracious enough to share some acting tips and advice. Dressed in a dapper white shirt, blue tie, suspenders, and with a baritone voice that anybody could identify in any given setting, Charlton Heston delivers the dialogue, “Every actor thinks he stinks…”, while Joey listens wrapped only by a towel. We loved the scene! So carefully crafted without trying too hard. Probably also the reason Friends is still one of the best shows to watch on Netflix all year round, or say a few weeks if you’re a die-hard fan and binge-watcher. Watching Heston in a commanding role certainly suited the star status he garnered after performing in films like The Ten Commandments and Ben-Hur.

Monica’s gloriously mustached and much older boyfriend Dr. Richard Burke was played to perfection by Tom Selleck. He was one of the longest relationships Monica had, apart from Chandler of course. Selleck first appears in the episode The One Where Ross And Rachel...You Know. Phoebe and Monica are catering for his party when he notices how thin Monica has become, indicating that he is seeing her after a long time. Richard and Monica get to talking and the tension between them is undeniable from the get-go! They probably had some of the most paused moments on screen. Selleck’s serious acting skills and natural charm led to him guest-starring in nine different episodes from 1996 to 2000, impressive numbers for a guest star! And his talent didn’t go unrecognized. In 2000, Tom Selleck was nominated for an Emmy for Outstanding Guest Actor in a comedy series for playing Dr. Richard Burke in Friends. Certainly a well-deserved nominee in our opinion!

Who can forget the out-of-breath, middle-aged stripper at Phoebe’s bachelorette party? Danny DeVito plays Officer Goodbody, who is the exact opposite of what Phoebe wanted, but after he dissolves into tears, she encourages him to finish the dance. He finishes it alright, but is then taken to the ER right after. DeVito's Friends cameo in The One Where The Stripper Cries was a roller coaster of emotions. He had three decades of an illustrious career to show for his acting talent, so the producers didn’t have to worry about giving him the role. And you’d think that he couldn’t do better than he did on set—the character of the sensitive male stripper was portrayed to the T. But when DeVito was asked about his role, years later, he responded saying he wished he removed some more pieces of clothing in the scene. That’s Danny DeVito for you...still cracking us up decades later.

Before Ellen Pompeo was known as Dr. Meredith Grey, she was Missy Goldberg who used to “make out… a lot” with Chandler back in high school. Chandler and Ross had a pact to not date her and she reveals this little nugget of information when Ross brings it up at the high school reunion. Way to be a friend Chandler Bong! Ellen Pompeo’s role was short and sweet, similar to Brooke Shields and Winona Ryder’s guest appearances, with the purpose of unveiling a little backstory of the lead cast. Watching Ellen Pompeo in a completely different role was a lot of fun watch in the high school flashback, with a high ponytail, earrings, and rocking the 80s style. She appears in the same episode in which Danny DeVito made his cameo, i.e., The One Where the Stripper Cries, so you can catch both these stars there.

Ben Stiller played Tommy, one of the oddest boyfriends Rachel ever dated. As THE SCREAMER, Stiller had a pretty short fuse and yelled at anyone who annoyed him in the slightest. He even yells at the chick and the duck! Dude really? Ross catches Tommy losing his mind and screaming at people, but the rest of the characters don’t believe him...until they hear for themselves. Watching Rachel and Phoebe flinch in front of a screaming Tommy was hilarious! He doesn’t get away with his act when Chandler catches him going off on his pets though. Good for Rachel.

The casting for the character of Tommy was obviously spot on given Stiller’s strong voice is perfect for the bully archetype. With several funny moments, Ben Stiller’s portrayal of the role definitely gave the show one of its top-tier comic episodes. With Stiller playing a guest role so well, it's no surprise that he is considered one of the top actors in the industry!

In the episode The One With Frank Jr., the ageless beauty shows up as herself. She is on Ross’ list of celebrities he’s allowed to cheat with. Rachel being Rachel, wants to see him flirt with the actress knowing fully well he just might humiliate himself. He does, but not before Rachel delivers her witty dialogue, “He’s about to go hit on Isabella Rossellini. I’m just sorry we don’t got popcorn.” Although Rossellini has only around three minutes of screen time, she exudes class and grace effortlessly, probably because she was a real superstar.

By the time Rossellini appeared on the set of Friends, she had three decades of acting credits from films including A Matter of Time, Blue Velvet, and Death Becomes Her. So the applause from the audience that follows Rossellini, as she walks from the Central Perk’s doorway to the order station of the cafe, wasn’t surprising. Ross’s reaction when he sees her, jaw-drop and all, certainly mimicked our reaction.

Monica’s uber-rich boyfriend Pete Becker gets into mixed martial arts and gets the living daylights kicked out of him. Yes, that was Jon Favreau before Iron Man and The Jungle Book happened. This directorial genius portrayed the role of Pete Becker so well that few fans secretly hoped Monica and Pete would work out eventually. The love story arc of Monica and Chandler obviously made up for Favreau being only a guest actor. But we’ve got to say that as for Monica’s exes, Pete and Richard were ahead of the pack. For Favreau’s 54th birthday, the sitcom's social media pages celebrated the actor by posting a funny clip from the show. It showed him with his torso and hands covered in cast moving restrictively from side to side. The cast comes from miserably failing toward his desire of becoming the Ultimate Fighting Champion, a scene we’d remember Jon Favreau by!

The husky-voiced, veteran actress’ role as Chandler Bing’s father is fondly remembered even now by all Friends fans. But according to Kathleen Turner, she didn’t have a very pleasant time filming the role. The six leads were a very tight clique, and the actress didn't feel welcomed at all. Sounds similar to what Paul Rudd had to say, but can we blame the cast? Kathleen Turner, on the talk show Live with Kelly and Ryan, mentioned that she was touring a one-woman show (portraying the diva Tallulah Bankhead), when Friends co-creator David Crane asked her if she would play Chandler’s dad. She added hilariously, "And I thought, 'Well, a woman playing a man playing a woman... I haven't done that yet. Why not?'" She accepted the role and although she felt sidelined on the set, the audience definitely admired her amazing drag queen persona.

Playing her character Jamie Buckman from the hugely popular sitcom Mad About You, Hunt attempts to order a coffee from Phoebe Buffay, mistaking her to be Ursula. Lisa Kudrow played the waitress Ursula on Mad About You. Ursula is actually the name of Phoebe Buffay’s twin sister on Friends. Clever huh?!

This crossover stint was surely a hit with the crowd. We heard the studio audience cheer as soon as Hunt entered the legendary coffee house. She ran her hand through her shiny blonde hair and swept us off our feet. Then, with sharp dialogue delivery, she fit into the scene so easily that it didn’t seem like she was only on the set for a little time as a guest star. That says something about her gifted acting talent if it was not already too obvious from her award-winning role in her television sitcom.

Paul, the big and intimidating father of Ross’ student girlfriend, starts dating Rachel. And hilarity ensues! Bruce Willis’ tough guy act punctuated by some side-splitting “neat guy” scenes makes these some of the funniest episodes in the series. When Willis enters the frame for the first time, he commands the entire scene before uttering a single word. He wears the stern-strict dad look and Ross knows instantly there’s no messing with this gritty guy.

We thought that this was yet another job well done by the casting Willis, but that wasn’t entirely the case. In 1999, Matthew Perry and Willis made a bet while working on The Whole Nine Yards. Perry bet Willis that their film would be a success, although Willis felt otherwise. And guess what? Perry was right. The film was a hit and as per the bet’s clause, Willis was to star on the show. He took home an Emmy for playing Paul though, and his film was a hit, so both stars won bigtime.