One thing I've learned as an actor as well as a producer is to trust my own instinct. When I first started acting I would sometimes have ideas about certain things, whether it's a scene, or a character or certain dialogue, that wouldn't be followed. I was never in a position to have the power to press the matter. Sometimes it wasn't even about my character. But I'd watch the movie afterwards and think I was right.

The truth is never pretty.

I sang in a rock band when I was training as a lawyer. You know, not professional, we just did it for fun. We just did gigs all over Edinburgh and some in Glasgow and some at festivals.

You know that every bead of sweat falling off your head, every weight you've pumped - the history of that is all in your eyes.

I have a level of fear going into every project, and that's what keeps me going.

So many actors get caught up in their technique, and to be honest, I see it really getting in the way. I see them forcing things. I definitely do my best work when I'm free of that. But I think as an actor, I work really hard in preparing the roles. I spend like 90 percent of my waking moments walking around thinking: "What does this character do? What is his relationship with so-and-so?" Always, really. Too much!

There's always advantages and disadvantages to doing any role. And there's a great sense of achievement, testosterone, fun, being able to live out your masculinity when you play an action role, or an action-adventure, or a real tough-guy role. Really, if you're doing a comedy, you can sit back and relax. And it's good to know that at the end of the day, you don't have to run off for another two hours and go to the gym, or go spend the rest of the night swordplaying with stunt guys. Then I think, "Oh my God, I love comedy.".