Sean Penn as Eric
Sean Penn appears in two separate episodes of “Friends” as Eric. In season 8, episode 6 “The One With The Halloween Party” he is engaged to Phoebe’s twin sister Ursula. He appears in the following episode as the same character, but goes on a date with Phoebe after breaking it off with Ursula. According to some sources, Penn appeared on “Friends” because his kids loved watching the show.