According to a witness at the No on H8 show at The ­Improv in Hollywood on Dec. 16, Twilight star Robert Pattinson, 22, booed a comic who said, "Here's my impression of Heath Ledger," then collapsed and began faking convulsions.

"Robert and his friend went nuts yelling at him," the source tells Us Weekly. "[Pattinson screamed] f--k you! You suck!"

But the actor -- who recently cut his famous hair -- went unrecognized by the performing comic.

"The comic didn’t know who it was, but I'm sure he found out later!" the source tells Us.

Source: US Magazine.com