You’d think a guy who went through rehab would stay off the sauce.  Not Ben Affleck who’s been spotted sucking down vodka at the Sundance Film Festival.

Affleck who went through rehab for a sobriety prob in 2001 has fallen off the wagon reported.

Affleck was at the Robert Redford film fest in Utah  to promo new movie The Company Men and hit the swinging after party.

At the party, Affleck "immediately sat down at a VIP table and grabbed the bottle of Absolut in front of him and poured a drink," a source said.

Pubbers, Sundance staffers and other attendees were stunned because Affleck is an admitted alcoholic.

They quickly got rid of all the photogs near the party area in an attempt to protect the star.

Too late.