And Cirque du Freak, by Darren Shan, is about a young boy who becomes a half-vampire.
Heyman says he's "very excited" about both projects.
Ideas for Azkaban
Before those come to the screen though, he's working on Harry Potter and the Prisoner of Azkaban.
It'll be directed by Alfonso Cuaron. They've already been to Edinburgh to discuss ideas with JK Rowling.
"We sat down with her and talked through some Alfonso's initial thoughts for the third film, and she was thrilled," Heyman reveals.
In the meantime, the world premiere of Chamber of Secrets will be in London on 3 November.