Robert Pattinson now confesses he's no hero to PETA ... turns out he never had to put his foot down over an order to masturbate a dog.
The actor said on Jimmy Kimmel's show Thursday the director of his new movie, "Good Time," asked him to perform the act but he refused and the director relented and allowed Pattinson to perform the act on a prosthetic dog penis.
PETA was outraged, comparing the director's demand to child molestation and praised Pattinson as a hero.
Now Robert says the whole thing was meant to be a joke. The question ... since he's an actor did he try to make us believe him to score some attention for the flick?