MATT DAMON sympathised with pal George Clooney on the set of new thriller SYRIANA because he had to pile on the pounds to play a CIA agent and was miserable about being so heavy.

No stranger to having to drastically alter his look for film roles, Damon reveals Clooney was nothing like his usual affable self on the set of the movie.

He recalls, "He had put on all that weight and he was really depressed. George was like that because he's a really active guy and he couldn't move around. He had to just sit there.

"I'd never seen him like that before. He's normally the life of the party but he was really depressed."