Every audition I get, I agonise over and I put everything I can into it.

I was nervous about playing a lead part in a Working Title romantic comedy and I was also nervous about the fact that I not only had to take my clothes off, but get my willy out. There's certain things you can do to make yourself look better, but there's nothing you can do about your willy. Your willy is your willy and no amount of working out is going to make your willy look any different. You get what you're given. But I wanted to look my best and to whip myself into any semblance of handsomeness. And that was hard going.

I never mind talking about my dad. I'm proud of who he is, and being his son is one of the things I'm most proud of. To be constantly compared to someone so brilliant, who happens to be your dad, is cool.

Because I was always a fat child, I got fatter and fatter, and I ended up 18 stone and with a 40-inch waist.

I've done loads of things people have never seen, dramas on BBC4 and plays upstairs at the Royal Court and the Bush, and because I didn't go to drama school, they gave me an education.

I watched what I ate for a bit and did a bit of exercise. I wanted to look alright because I knew I had to take my clothes off and I knew I was starring alongside some extremely attractive women! I think it was Humphrey Bogart who said that the only reason people found him attractive was because of the attractive women he played opposite. So, as audience member you go: "Well, if she would find him attractive, then surely I must too!" Playing opposite beautiful actress of the calibre of Rose Byrne and Anna Faris is amazing - it does a lot of the work for you.

There's nothing so unattractive as vanity... particularly male vanity.