All the Celebrities You Didn't Realize Guest-Starred on 'Friends'!

Brad Pitt

Played Will Colbert, who was the president of the “I Hate Rachel Green Club” in high school, in season 8 episode 9. He was married to Jennifer at the time.

Christina Applegate

Played Rachel’s sister Amy Green in season 9 episode 10 and season 10 episode 5