How would you describe working with Matt Damon?
You can see he's got a history of being a writer and he's very inventive. He's courageous and will try anything, even if it makes him look cowardly. [Laughs.] Especially cowardly. That was inspiring. Not a lot of actors are willing to do that. I learned a lot from guys like Matt and Jack [Nicholson].
Your co-star Leonardo DiCaprio said you didn't mind looking cowardly...
Look, sometimes you've just got to make an ass out of yourself. You just do it.
Being from Boston - where the movie was set - we hear you gave Leo a stern warning about getting the Boston accent right.
Yeah. [Laughs] He's one of the only actors in history that ever got the Boston accent right. It's one of the hardest accents to get. It's like someone doing an Aussie accent - it's almost impossible to get it right and it almost hurts your ears when you're from that place. So I was relieved when he opened his mouth that he got it.
Who has given you the best advice about Hollywood?
MIckey Rourke. He sat me down and said, "Don't mouth off to people in Hollywood, like I did. You gotta be on time and disciplined. I f**king blew it." It still sticks with me at the end of a long day of rehearsals - or doing one more interview!
There's a reason Matt Damon is one of Hollywood's hottest, most beloved actors. Sure, his all-American boy-next-door looks and trademark smile make him easy on the eye. But what stands out in most people's minds is his nice-guy reputation, particularly when it comes to his adoring public.
"I just feel blessed to be able to do what I do, so why have airs and graces when the only thing separating me from everyone else all boils down to luck?" says Matt, 36.
Surely talent must figure in there somewhere, but it's the little touches - like always taking the time to sign an autograph or have his photo taken with fans - that make this humble heart-throb a class act.
Matt describes his Miami home as his "favourite place in the world."
"Some people embrace the showbiz thing, but for me, it's not worth risking my private life being public. My wife and family mean the world to me, and I don't want them to fall into the trap of being hounded by the press because of what I do."