Tom Felton, Joshua Herdman & Jamie Waylett - Draco, Goyle & Crabbe.
Harry Potter's arch-enemy and his two Slytherin goons talk to the Blue Peter team about how they were chosen, their favourite bits and the worst things about their characters.
Click here to watch the interview, or scroll down to read it
How on earth did you get your parts?
In my primary school we were reading the Harry Potter books and someone told me there was going to be a film of Harry Potter and I thought oh that's going to be cool, I said - When's it out? I didn't know it hadn't even been made yet.
The people who were casting everything came to our school, they picked four of us out, spoke to us and then took polaroids - that was the last I heard. And then they told my headmistress that they wanted to see me again and it just kicked off from there.
Now you all play bad characters, Joshua, tell me, what's the worst thing about your character?
I suppose just being a bully basically, looking mean, following Draco about.
It looks like an epic of a movie, how long did it take to film Tom?
About six or seven months.
And we know also that they're already making the second Harry Potter movie - are you involved Tom?
Tell us Jamie what were the sets like and what was it like actually going into Hogwarts?
Well the great hall was very grand, it was how I sort of imagined it, it's really glittery.
And did they actually film the whole thing there Jamie?
Yeah in the studio.
Each of you in turn, what's your favourite scene?
Jamie: Well my favourite scene was the Halloween scene where because the tables come up to about my knee height we had to get out when we have to get out because everyone starts screaming and they have to run.
I kept falling over my robes and then I kept falling over about five times - I kept falling over and it hurt.
Tom: The flying scene where I had to fly outside, that was fun.
Jamie: I think the Halloween scenes as well.