While shooting a PSA for his clean water organization OneXOne, Matt Damon lost his cool and went on an F-bomb heavy tirade against Adrian Grenier.
'Dont get f***ing smart dude. If you don't want to do it walk away," he says. "F** you. Go f*** yourself!"
Grenier continues to fumble his lines while Jeremy Piven tries to play peacemaker.
Surprise, not for real! The stunt is a promotional bit for the season finale of 'Entourage' on October 4, when Damon makes a cameo to promote his real-life charity.