Rupert also told the magazine that his favourite scenes to film in the Prisoner of Azkaban were at the Whomping Willow.
"I was supposedly being dragged along by a dog, but this guy was pulling me along the set."
His other fave shots were in Defence Against the Dark Arts when Professor Snape is dressed as a woman, which he found "very funny".
Rupert also gave hints as to what he would like to be when he is older.
"When I was younger, I wanted to be an ice-cream man.
"I'd like to be a cartoonist as well. I like drawing a lot; I especially like cartoons, I really love Spongebob."
The dark side
The trio all said how much darker POA is going to be compared to the first two.
And it is not just seeing the Dementors that makes it a scarier production, explained Daniel Radcliffe. We see the dark side to Harry too.
"He actually does have murderous thoughts.
"Literally, he would kill Sirius Black if he got the chance," he said.
We can't wait!