"Even if the trailer or an advert for it comes on, I change the channel.
"I'm not ashamed, but it's like I can't relax if that's on.
"About three years ago was probably the last time I saw any of the first films and people always seem amazed that I can survive without watching it annually, but I can and do, happily. I am proud of the first film because it's a great kids movie, but I was a kid when I made it and it's like seeing baby photos passed round. It's not pleasant."
He also talked about some of the crazy things that have happened to him with the fans.
And he admits he has had some strange fan encounters.
"Mrs Radcliffe was funny," he said. "She was a girl in New York who said 'I'm the next Mrs Radcliffe'. The next Mrs Radcliffe, like I'm married already.
"So she was obviously kind of mental, she actually tried to climb into the car.
"The strangest reaction I've ever had was probably before the first film even came out. I was walking down the road in France, on holiday with my mum and dad, and I looked over at the girl to my left, and she looked back at me and just screamed in my face. I, not thinking, ran. It was a really stupid thing to do."
He also admitted to being star struck himself.
"I met Kate Hudson not long ago, I used to have a really big crush on her because of Almost Famous. I also met Lily Cole very briefly and was a gibbering wreck.
"But getting a kiss on the cheek from Sophie Dahl was a highlight of my life. I actually did say to her you've just given me closure on my adolescence."
While performing for Equus, he worked really hard at rehearsals because he wanted to make sure to get it right.
"I thought, if I screw this up then it's going to be bad because the knives are drawn and ready.
"So I just worked hard and I'd been training for 18 months to be able to be heard at the back of the stage. There's an assumption that you can just stroll onto the stage and do it. You can't. You need to train.
"The best one was America, of course, because they really didn't like the nude thing.
"They got very puritanical about it all. It was also because at that point in America I was a minor, which I thought was funny."
Dan says he rather likes dark movies and feels that, as far as kids' movies go, he thinks the Harry Potter movies tend to lean a bit spooky, but they're funny, too.
"As an actor, I've always leaned towards the dark side. I'd rather read a dark, intense book than something light and fluffy.
"I'd rather watch There Will Be Blood than, say, 27 Dresses.
"I like to think that in Potter we are as hard-hitting as kids' films go, but we also get them laughing too.
"I hate all this c**p about, 'oh we're scaring kids too much.'
"Kids love being scared. As a kid I saw Jumanji and had nightmares about spiders for weeks, but I loved it.
"There is this culture where we think kids are going to be damaged by it, but they're not. Ultimately the stories are about good triumphing over evil, which is a formula that's been going on for centuries."