James and Oliver Phelps play the mischievous Weasley twins in the Harry Potter films.
Newsround Online caught up with them to find out Prisoner of Azkaban and their future.
What do the Weasley twins get up to in this movie?
James: There's the Marauder's Map scene, when Fred and George give Harry the secret map to show him around different passage ways in Hogwarts, which was a good scene.
What was it like working with the new director Alfonso?
Oliver: Well, both Chris and Alfonso were great to work with. Alfonso was a bit more hands on I suppose. When we were filming the Maruader's Map scene, he kept changing the ways of doing it to get all the angles he could from it.
What do you think of the stuff the Weasley twins get up to in Order of the Phoenix?
James: It's fair, I suppose, how the characters would go. They do come a bit off the rails, and at the end of the day they do what they want to with the school.
Did you get to do much Quidditch with this movie?
James: Yes, there is some Quidditch in it. Obviously, in the book it's raining a lot, so it was a lot different to all the other filming of the Quidditch. We don't want to say too much about it, but we did get very wet!
What's it like meeting up for each new movie?
Oliver: It's like coming back to school after a long holiday. Meeting up with friends. We've known each other for three or four years now. It is like a school reuniting after a summer break.
And have you started the fourth film yet?
Oliver: We haven't started properly yet, although pre-production is underway. We'll be getting going shortly.
How will this film differ and what should Weasley twins fans look forward to the most?
James: Well, Oliver and I have our hair longer in this one. And there's lot more movement in some of the camera angles.
Oliver: We're looking forward to the Marauder's Map scene because that took a long time to do, so it will be good to see how it turns out
In the books, the Weasley twins get up to the most mischief. Are you both like that on the film set?
Oliver: I wouldn't say we get up to the 'most', but we do get up to some mischief on set! There's no one in particular who stands out from the rest, but we do have our moments.