Stars You Forgot Appeared in Famous Sitcoms Michael, May 18, 2026 Famous sitcoms are full of familiar faces. Some guest stars were already huge when they appeared. Others were rising actors who became much more famous later. A few showed up for one quick joke, one awkward date, one family episode, or one strange cameo fans only remember on a rewatch. That is part of the fun. A sitcom appearance can feel small at the time, then become surprising years later when the actor’s career grows in a completely different direction. Here are the stars you may have forgotten appeared in famous sitcoms. Brad Pitt Source : Instagram/bradpittofficiallll Brad Pitt’s Friends appearance remains one of the show’s most memorable celebrity guest spots, but it is still easy to forget how funny the setup was. He appeared in the Season 8 Thanksgiving episode “The One with the Rumor” as Will Colbert, an old high school classmate of Ross, Monica, and Rachel. The joke was that Will looked like Brad Pitt but absolutely hated Rachel Green, played by Jennifer Aniston, who was Pitt’s wife at the time. Julia Roberts Source : Instagram/juliaroberts Julia Roberts appeared in the post-Super Bowl episode of Friends, one of the biggest guest-star events in the show’s history. She played Susie Moss, a former classmate of Chandler Bing who seemed interested in him years later. The twist was that she had not forgotten how Chandler embarrassed her when they were kids. Roberts’ episode aired in 1996 as part of the two-part “The One After the Superbowl.” George Clooney Source : Shutterstock Before George Clooney became an Oscar-winning movie star and director, he was already a major TV heartthrob because of ER. That made his Friends appearance especially clever. Clooney and Noah Wyle appeared together in the Season 1 episode “The One with Two Parts: Part 2,” playing doctors who go out with Monica and Rachel. Noah Wyle Source : Instagram/therealnoahwyle Noah Wyle appeared alongside George Clooney in that same early Friends episode. At the time, Wyle was rising fast because of ER, where he played Dr. John Carter. On Friends, he played one of the doctors Monica and Rachel meet after Rachel hurts her ankle and uses Monica’s insurance information. Robin Williams Source : Instagram/therobinwilliams Robin Williams made a brief but unforgettable appearance on Friends with Billy Crystal. The two comedy legends appeared in the Season 3 episode “The One with the Ultimate Fighting Champion.” They were not part of the main plot for long, but their scene at Central Perk became famous because of how strange and spontaneous it felt. Billy Crystal Source : Wikipedia Billy Crystal’s Friends cameo came in the same scene as Robin Williams. Crystal and Williams played two men having an emotional conversation at Central Perk while the main characters awkwardly listened nearby. The scene is brief, but it stands out because it feels almost like a comedy sketch dropped into the middle of the episode. Bruce Willis Source : Instagram/brucewillisok Bruce Willis appeared on Friends as Paul Stevens, the father of Ross’ young girlfriend Elizabeth. The role could have been a simple tough-dad joke, but Willis made it funnier by playing Paul as intimidating, guarded, and unexpectedly vulnerable. His scenes with Jennifer Aniston’s Rachel became especially memorable because Paul’s serious exterior kept cracking. Christina Applegate Source : Instagram/christinaapplegate Christina Applegate appeared on Friends as Amy Green, one of Rachel’s sisters. Amy was spoiled, blunt, self-absorbed, and completely unaware of how rude she sounded. Applegate played the role with perfect comic confidence, making Amy irritating in exactly the way the show needed. Jon Favreau Source : Instagram/jonfavreau Before he became one of Hollywood’s most important directors and producers, Jon Favreau played Pete Becker on Friends. Pete was Monica’s wealthy boyfriend in Season 3. He started as a charming tech millionaire, then took a strange turn when he decided he wanted to become an Ultimate Fighting Champion. Favreau appeared in several episodes, including “The One with the Ultimate Fighting Champion.” Bryan Cranston Source : Instagram/bryancranston Before Breaking Bad, Bryan Cranston had a memorable recurring role on Seinfeld. He played Tim Whatley, Jerry’s dentist. The character appeared in multiple episodes and became one of the show’s most memorable side figures. Years later, Cranston and Julia Louis-Dreyfus even joked about their Seinfeld history at the Emmys. Courteney Cox Source : Instagram/courteneycoxofficial Before Friends made her a defining sitcom star, Courteney Cox appeared on Seinfeld. She played Meryl, Jerry’s girlfriend in the Season 5 episode “The Wife.” The plot centered on Jerry and Meryl pretending to be married so they could get a dry-cleaning discount. The episode aired in March 1994, just months before Friends premiered that fall. Mariska Hargitay Source : Instagram/therealmariskahargitay Mariska Hargitay is now almost impossible to separate from Law & Order: SVU, but she also appeared on Seinfeld. In the two-part Season 4 finale “The Pilot,” she played Melissa Shannon, an actress auditioning to play Elaine in Jerry and George’s fictional NBC pilot. James Spader Source : Instagram/jamesspader.jts James Spader appeared on Seinfeld as Jason “Stanky” Hanky in the episode “The Apology.” The character is part of a recovery program and apologizes to people he has wronged, but George becomes furious when he does not receive the apology he believes he deserves. Spader’s dry, serious delivery made the absurd situation even funnier. Lauren Graham Source : Instagram/laurengraham Before Gilmore Girls, Lauren Graham appeared on Seinfeld. She played Valerie, Jerry’s girlfriend in the Season 8 episode “The Millennium.” The plot involved speed dial rankings, with Jerry becoming competitive about where he stood on Valerie’s phone. Denise Richards Source : Instagram/deniserichards Denise Richards had a memorable appearance on Seinfeld in the episode “The Shoes.” She played the teenage daughter of NBC executive Russell Dalrymple. The episode became controversial in its own way because George gets caught staring at her cleavage, creating one of the show’s most awkward plots. Sarah Silverman Source : Shutterstock Sarah Silverman appeared on Seinfeld before becoming known for her own sharp comedy voice. She played Emily, Kramer’s girlfriend in the Season 8 episode “The Money.” The plot involved sleeping arrangements, insomnia, and Kramer’s relationship becoming strained by constant restlessness. Amy Adams Source : Shutterstock Before she became a multiple Oscar nominee, Amy Adams appeared on The Office. She played Katy, a purse saleswoman who visits Dunder Mifflin in Season 1 and later briefly dates Jim. The role came before Adams’ biggest film breakthrough, which makes it especially fun to revisit now. Idris Elba Source : Instagram/idriselba Idris Elba is now known for intense drama, action roles, and a commanding screen presence, but he also appeared on The Office. He played Charles Miner, the serious new boss who arrives at Dunder Mifflin and immediately changes the office dynamic. The joke was that Charles was far more polished and intimidating than the usual Scranton chaos. Kathy Bates Source : Shutterstock Kathy Bates appeared on The Office as Jo Bennett, the powerful CEO of Sabre. Jo was blunt, confident, Southern, and completely unimpressed by nonsense. Bates brought real authority to the role, making her feel like someone who could casually walk into the Scranton branch and reset the entire energy. Jack Black Source : Instagram/jackblack Jack Black appeared in one of The Office’s strangest celebrity cameos. He did not visit Dunder Mifflin as himself. Instead, he appeared in a fictional movie that Jim, Pam, and Andy watch during the two-part episode “Stress Relief.” The fake film also featured Jessica Alba and Cloris Leachman. Featured Image : depositphotos Entertainment & Media