George Clooney once left Arnold Schwarzenegger in a drunken stupor, after cheating his way through a drinking contest.

While working on their 1997 movie Batman + ROBIN, Clooney rose to Schwarzenegger's challenge in defence of his Irish roots.

But when Clooney realised he couldn't match the TERMINATOR star, he decided to cheat.

Clooney recalls, "He was bragging that he could outdrink any Irishman. You don't do that. It's not right.

"He had this bar and restaurant, I don't know if he still has it, and he had a big dinner. James Caan was there and all these people were there and he was drinking peach schnapps. It's not right. And it's clear and horrible.

"I did a couple of shots of that and I was like, 'I'm not gonna hang with this guy. He's gonna kill me.' So I gave the waitress $500 to keep bringing me shots of water and bring him shots of peach schnapps.

"Every five minutes, he'd be sitting there talking to (his wife) MARIA and I'd be like, 'Hey, let's go! Come on superstud, let's go!' I got him literally about 15 shots in and he was just sitting there (slumped over the table).

"I never told him (that I cheated), actually."