I'm quite ignorant about fashion and I'm colourblind, so it's all a tad tricky. My only knowledge of that world comes through Christopher Bailey, whom I first met in 2008 when I did a campaign for Burberry that featured musicians, artists, actors and sportsmen.

I always think of comedy as being spontaneous, and yet everything about filmmaking is not spontaneous.

As an actor there's a lot of scrutiny and, even when you've had success, it becomes about sustaining that success. A friend of mine described it as a peakless mountain. Even for Robert De Niro there's Al Pacino and for Pacino there's De Niro.

Actors who perhaps are super-confident and have absolute belief in themselves I always admire, because I can't really be like that.

Listen, acting is not surgery, it's entertainment. You're doing something to hopefully move people, to make them laugh, to transport them. But actors are vulnerable, and the reason we're vulnerable is that we're always trying to recreate human behaviour.

People ask, "Do you enjoy acting?" But you only have those specific few hours to do a scene, and then you drive home and wait for six months to find out how it went. You can't go back and put in a new idea. Filming is about continuing to be alert and to think, and I find it quite exhausting. Certainly I would say that fear is a part of that.

Making 'Birdsong,' on the one hand you have how prestigious it is and the reputation of the book, which is something that's an extraordinary piece of work. Sebastian Faulkes is a genius. So you feel that responsibility when you're portraying that character that he's imagined and millions of readers have pictured.