Moths are the ones that freak me out. It's something to do with the way that, if they get squashed, they turn to dust. There's something very wrong about that. It all feels a bit Gothic.

Getting the call to be in The Goblet of Fire was like being welcomed into the most exclusive upper circle of some elite actors' club. You sit on set with the cream of the National Theatre and the RSC, all clutching wands or wearing witches' hats.

When you're playing a real person there's a balance between playing the person in the script and playing the person as he was in life. You have to be respectful and true to who that person was, but at the same time tell the story in the film.

I was always going to act, literally ever since I was tiny. In fact, I have Doctor Who to thank for that. I wanted to become an actor after being obsessed with Tom Baker, the fourth Doctor Who, in the 1970s. His was the definitive performance of all time in anything.

I've always been a geek and slightly awkward… slightly umm… I was never the cool kid at school.

And the very fact of how you speak somehow influences who you are. The way you move, the way you think, it seeps into your being, and it's quite hard to really break that down entirely.

Back in 2005, when I was Christopher Eccleston, we saw one of the largest increases on record, of CO2 in the atmosphere. Unless we keep the rise in global temperature to under 2 degrees, by the time I'm Daniel Radcliffe or wee Jimmy Crankie, I won't be able to save the planet. I won't be here to help you -- well I might, but I'll be that bloke who won Any Dream Will Do.