I change myself a lot. Some roles you don't want to be big, bulky, muscle-y guy and some roles you want to be a lean, marathon-runner physical type. And some roles you just don't want to be in shape.

When I look at myself in the mirror, I don't see the bad guy.

I'm a trained actor and I can always tone it down, I can always simplify the work I've done. But if I'm asked to bring the nuanced and complicated work, I'll have it in my pocket, and all that information helps.

When I came on to Jack Reacher, I had just taken my girlfriend on vacation and ate everything I could. I put on about 15 pounds, so when I met [the Jack Reacher team] I was clocking in at about 180. They looked at me and were like, "You're just gonna lose five pounds, we're gonna keep you skinny".

You get a role like this in a big action movie [like Jack Reacher] and you can go one of two ways: you can paint in broad strokes, which happens a lot in action films, or you can get very detailed.

I'm not a method actor but it certainly does help to have that kind of dedication. I treated my preparation like I was in the military. I didn't go out ever. I went out for drinks probably twice in five months. I lived very monastically.

My character is called The Hunter. He's the main antagonist in the movie. In a nutshell, he's a slightly deranged natural born killer who's weirdly determined to succeed at his job, whatever his employment is. He's a mercenary and there's a high body count for him in this film [Never Go Back].