"I found out slightly before everybody else in the world did so I was slightly prepared when people rang me shouting: 'he's been cut, he's been cut'.
"It's a shame because Sean played the Quidditch Captain very, very well. He's a lovely guy and it'll be odd not having him around."
Chris said the Prisoner of Azkaban would be very different from the first two films. He said it was darker and more grown-up.
That's partly because of new director, Alfonso Cuaron, who's replaced Chris Columbus.
"His style is completely different to Chris Columbus'" Chris said. "I shouldn't talk about it really, but it's all going to do with the camera shots and lengths of takes.
"He's going for a real dramatic, tension building to a climax kind of film which I think is going to be perfect for Potter three."