But he says he won't get to help decide who plays her.
Harry meets Cho Chang for the first time in book three, Harry Potter and the Prisoner of Azkaban. There's instant chemistry between them, which develops even more in book four.
"It was really creepy actually because Aragog was really there," he said.
"But I think it was worse for Rupert than it was for me cos Rupert is actually scared of spiders."
"At first, he's really shy but then you get to know him and he's completely mad, he's really cool, I really like him," Dan said.
And although Dan's due to start filming The Prisoner of Azkaban next year, he admitted he doesn't know if he'll be doing film number four.
"I'm definitely doing the third and after that I have no idea what's going to happen," he admitted.