Dustin Hoffman's attempt to surprise reporters with a guinea pig in his pocket came back to bite him when the critter started gnawing on his nipple during a press conference for his new film.

Hoffman was promoting animated mouse movie The Tale of Despereaux and was desperate to entertain himself while reporters fired off questions he had bored of answering during previous interviews. And after spending time with his rowdy young son and his pal's pet guinea pig, the actor got the idea to stick his furry new friend in his shirt pocket.

He muses, "You feel like it's presidential, and it's kind of silly. So for Despereaux... I rehearsed with the guinea pig and everything - it was doing great. I took it to the press conference and suddenly it bit my nipple. I haven't lactated since."

(This news article provided by World Entertainment News Network)