25 famous actors you didn’t know appeared on Friends

18. Robin Williams and Billy Crystal

Tim and Tomas – “The One With the Ultimate Fighting Champion” – S3E24

Usually the opening credits are just an opportunity to slip in a quick joke or set the scene for the episode. But the beginning of the “The One With the Ultimate Fighting Champion” remains one of the best opening credit scenes in Friends history.

The group is settled in their usual spot in Central Perk and Monica starts to tell them what happened between her and her billionaire boyfriend, Pete Becker. They’re interrupted by two gentleman, Tim and Tomas, who ask them to make room on the couch. The two men happen to be played by legendary comedians Robin Williams and Billy Crystal.

As Monica tries to continue her story, the group can’t help but overhear the discussion happening between the two men. Tomas, played by Williams, believes his wife is cheating on him with her gynecologist. His best friend Tim, played by Crystal, tries to console him but ends up revealing that Tomas’ wife is cheating on him… with him. The whole thing is hilarious, especially with Williams’ use of a foreign accent.

Knowing how talented Robin Williams and Billy Crystal are at improvising their comedy, there’s a good chance that much of the scene may have been unscripted. The parts about the gynecologist having access and an ooooozing wound sound like they’re straight from Williams’ stand-up act.