"She's really gracious, she's not territorial," he said. "She kind of recognizes the challenges of adapting (a book for a film) and she's really sympathetic to that."

"She said now that the shooting part is coming to an end she might just pop in more often, which we would love," Yates said. "She was so busy with all the other books she couldn't (visit much more than once a year)."

Chris Columbus directed the first two "Harry Potter" films, Alfonso Cuaron took on the third and Mike Newell directed the fourth before Yates took control of the final four movies.

"I wake up in the morning I think Potter, I got to bed I think Potter. By the time I finish I probably will have spent seven years doing Potter," Yates said.

"It's a challenge to bring this huge thing to a conclusion and I couldn't bear letting that go and seeing someone else doing it," he said. "I couldn't let it go, it was too addictive, too compulsive, too much fun."