Richard [Griffiths] was by my side during two of the most important moments of my career. In August 2000, before official production had even begun on Potter, we filmed a shot outside the Dursleys', which was my first ever shot as Harry. I was nervous and he made me feel at ease. Seven years later, we embarked on 'Equus' together. It was my first time doing a play but, terrified as I was, his encouragement, tutelage and humor made it a joy. In fact, any room he walked into was made twice as funny and twice as clever just by his presence.

Harry Potter star Daniel Radcliffe has confessed that until recently, he thought the 16-year-old fellow tween idol [Justin Bieber] was a female. 'I only heard Justin Bieber for the first time two weeks ago. I genuinely thought it was a woman singing. I'd never heard it before. Is it big in England yet?'

The paparazzi were outside the theatre every single night, but we came up with a cunning ruse. I would wear the same outfit every time - a different T-shirt underneath, but I'd wear the same jacket and zip it up so they couldn't see what I was wearing underneath, and the same hat. So they could take pictures for six months, but it would look like the same day, so they became unpublishable. Which was hilarious, because there's nothing better than seeing paparazzi getting really frustrated.

My job to make sure that thing is kick-ass - takes the mold, jumps on it, throws glitter all over it, smashes it, kicks it around, and drops the mic. If we don't do that, then we deserve not to have a hit.

In my experience of doing physical scenes, half of your energy is spent on trying to get the other actor to enter into it physically with you. Most actors don't want to hurt each other.

Working hard is important. But there is something that matters even more, believing in yourself.

As far as I can tell, most actors' main motivation is self-doubt and neuroses.