Because today is the 20th anniversary of Friends, we've put together a list of the BEST cameos over the years.
Which one was your favourite? Let us know...
The one with Robin Williams and Billy Cyrstal:
Brad Pitt was married to Jennifer Aniston, when he made this epic cameo as Will:
Reece Witherspoon played Rachel's sister:
How could we forget the time George Clooney popped by:
Charlie Sheen played one of Phoebe's old boyfriends:
When Julia Roberts made a cameo on the series, she made Chandler wear her underwear:
The One Where The Stripper Cries with Danny DeVito:
Two words.... Jennifer Saunders:
Ben Stiller played Rachel's new crazy boyfriend: