The 90s hit sitcom would not be complete without all the cameos that have made some of Hollywood's biggest stars over the years.
In an episode of Season Eight, Monica meets former high school classmate Will Colbert, played by Brad Pitt (then married to Jennifer Aniston, who played Rachel Green). Monica invites him to the band's Thanksgiving dinner.
As it turns out, Will has a long-standing grudge against Rachel, and he reveals at the table that together with Ross, he co-founded the club "I Hate Rachel Green."
The Reese Witherspoon
Reese Witherspoon appears twice in Season Six as Rachel's youngest sister, Jill.
She appears at the door of Monica's apartment for the first time after being financially cut off from her father, and at some point clashes with the "Will she or will not she?" Drama between Rachel and Ross.
Billy Crystal and Robin Williams
What do you get when two of the biggest names in the comedy play in the immediate vicinity of the Friends set?
This completely improvised scene with Billy Crystal and Robin Williams.
Crystal and Williams happened to be nearby while a third season episode was being filmed. The authors asked them if they were willing to perform, and they agreed.
Crystal and Williams play friends Tomas and Tim. They interrupt Monica while she tries to tell a story and ask the gang to make room on the orange couch in the Central Perk. The ridiculous conversation between the two supersedes everything that Monica wanted to share.
The one with Winona Ryder
In season seven, Winona Ryder played Melissa Warburton, Rachel's – sorry, Ray Rays – former sister of the college sisterhood, with whom Rachel once shared a kiss.
The Bruce Willis
Do you remember when Ross was his (much younger) student Elizabeth Stevens in season six dated?
Bruce Willis made a cameo appearance as Paul Stevens, Elizabeth's father, quickly making it clear that he is not satisfied with Ross's relationship with his daughter.
In season seven, Susan Sarandon played Cecilia Monroe, a soap opera actress who advises Joey on how to play her role in the series "Days of Our Life".
The ones with Tom Selleck
Before Monica and Chandler there were Monica and Richard – and he was played by none other than Tom Selleck.
The one with Danny DeVito
Who could forget Danny DeVito as Officer Goodbody, the stripper who booked Rachel and Monica at the last minute for Phoebe's bachelor party?
The Sean Penn
Sean Penn's cameo came during the eighth Season Phoebe's twin sister Ursula.
Phoebe soon discovers this Ursu la has lied to Eric to be with him, and things are changing.