PHOTOS: Growing Up 'Harry Potter': Daniel Radcliffe, Emma Watson, Rupert Grint

"You have to remember when I started, not all of the books have been published, and in a sense what she always put to me in one way or another was to follow the characters," he went on. "It was always about what detonated in Harry, Ron, and Hermione. That's what was most important in the books."

PHOTOS: Harry Potter London Red Carpet

His main goal: "I was never worried about spectacle. I figured if a spectacle-informed character was what was really rewarding to me as a fan and to the other fans, then I would do it. But for the most part, it was about character. And that's what Jo cares about."

He puts just as much pressure on himself to do the books justice as the readers.

"I'm a fan too , so I think at the end of the day, I'm probably the hardest on myself. I have a movie in my head, I try to get it on paper, which is the first challenge, and then I try to see it on the screen," he said. "I think we all feel that way. There's not one of us who isn't a Potter fan. We're as big of fans as anybody here."

And if he ever needs a little help, he can always count on Rowling.

"I once asked for background for myself about Ron's uncle and she sent me a four page email and none of that material is in the book. It's scary what she knows about that world," Kloves said.

Harry Potter and the Deathly Hallows: Part 2 broke records at the box office in midnight showings, earning $43.5 million -- beating The Twilight Saga: Eclipse, which raked in $30 million in midnight shows.

RELATED:

STORY: 'Harry Potter and the Deathly Hallows: Part 2' Takes Over Twitter

STORY: 'Harry Potter and the Deathly Hallows: Part 2': Matthew Lewis on Playing Neville Longbottom