Psychopaths don't have that charming skill set. They definitely manipulate, but they do it through focused, unskilled means. They're more obsessive.

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.

The role I played [in theatre] was originated by Ian McKellen in 1979 and he came. I didn't know he was there and I walked out at the end of the play, which is a very intense play - my character is required to do some really horrible things - and the director was waiting backstage and he goes, "Obviously I didn't want to tell you guys, but Ian was here today" and we, of course, freaked out.Ian McKellen said some really beautiful, kind things, one of which was, "It's so much harder to watch than it is to do."

I was eating with the help of a nutritionist so I was definitely putting in the appropriate calories and vitamins and minerals into my body; however, it was still so little that if I had the tiniest piece of sugar, my brain would go crazy. If I had some alcohol during the run of that play, my brain would go crazy.

Sociopaths are more complicated psychopaths; the difference between a sociopath and a psychopath is a sociopath is incredibly charming. There are a lot of sociopaths that are CEOs. They don't necessarily kill people but they're able to walk into a big social function and make everybody think they're the kindest, coolest, smartest, most interesting person in the room.

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".

The guy [Tom Cruise] is a machine.