I always try to describe making movies like summer camp, or some holiday where you spend all day, every day with a new group of people whom you kind of love and then never see again.
Most actors hate watching their own films because all you can see is the glaring mistakes, your own tricks and ticks.
A lot of people think theatre must be much harder work than film, but anything histrionic or superfluous gets seen on camera so you have to work to distil it into a complete sense of what's true.
Actors who perhaps are super-confident and have absolute belief in themselves I always admire, because I can't really be like that.
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.
I think all actors have a similar deal. You want some people who understand. Although it looks great - and is great - there are also shoddy moments when you feel really rotten, and when it's going well, you're not allowed to complain.
I feel like J.K. Rowling's world is one that is owned by everyone in some ways. People have grown up with it and have such a sense of that universe that there's something kind of wonderful seeing everyone get involved.
I do get stopped a bit now and then, but I can go to the supermarket and on the Tube without being noticed. It's usually me that gets starstruck, especially by TV stars.
And you can't complain about kissing Emma Watson. Isn't that what everyone in the world wants to do? I've known Emma for a few years. She's this amazing capacity of young and vibrant and brilliant, but also a bright, intelligent old soul.
I always think of comedy as being spontaneous, and yet everything about filmmaking is not spontaneous.
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.
In England we have this saying about Marmite: people either love it or hate it. That's like a lot of the movie work I've done. People either find it repulsive or find it really interesting and get engaged in it.
As a runner on a film, you are the lowest of the low, and yet you have incredible access to everyone. I can totally imagine that for actors in the middle of a Hollywood bubble, all they really want is a sense of normality, and that gopher can be a tap for that.
On so many levels, acting in film and TV is so much the sum of its parts, and somewhere in there, there's an alchemical thing that makes something happen or not - that makes something connect or not. Now, of course you want to make work that people see, but the enjoyment I get out of acting is playing characters.
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.
If you're an English actor and turn up in America, they don't have an opinion about where you sit. They have no idea what auditions to send you to, so they send you to everything.
If I do a film and have to get naked, that tends to dictate how often I go to the gym. Acting in 'Richard II' on stage was a huge physical workout, so I ended up more toned than I normally am.
Making a film or doing a play are completely different experiences and entirely fulfilling, but completely unique. I also think one complements the other. People often say that theater is about flexing your muscles, and is actually real acting, whereas I sort of disagree.
It's the weird thing Eton does - you're at school next to lords and earls and, in my case, Prince William, so you end up being used to dealing with those sorts of people.
I go to the theater two or three times a week when I'm in London. Whereas I feel guilty going to the cinema in the middle of the afternoon.
My first film, 'Like Minds,' was with Toni Colette, who was extraordinary. I mean it was basically a mini-masterclass for acting on film at a time when all you could probably see were my eyebrows bouncing up and down on screen.
Ladies and babies, and mortgages, for that matter, can all wait. Acting has done a strange thing to me, though. I often sit there, thinking, 'I love this, but I wouldn't put my daughter on the stage.'
Two years ago, I shot 'Pillars of the Earth' in Budapest - it was a big part, but I had a lot of time to sit around and visit cafes.
