"Fifty Shades of Grey" author E.L. James opened up in a rare interview with Entertainment Weekly about the madness surrounding the highly anticipated movie. James talked about the fans' disappointment with the Christian Grey casting, her hopes for the movie and what she loves about Dakota Johnson, who will play Anastasia Steele.

The 50-year-old author announced to the world via Twitter on Sept. 2 that Charlie Hunnam was cast as the kinky, dominating and insanely hot billionaire Christian Grey.

"The gorgeous and talented Charlie Hunnam will be Christian Grey in the film adaption of Fifty Shades of Grey," she tweted.

Moments after sending that tweet fans began expressing their dislike for the decision. Many thought Hunnam was completely wrong for the role. The author stayed silent on Twitter but told EW that she had to take a break from social media for a couple days because of all the negative comments.

"It was very mixed and I had to get off Twitter for a couple days. I wasn't surprised," she said. "People hate change. I thought there would be a few people upset, regardless of whom we had chosen. It was intense, but people came around to it."

A little over a month after that casting announcement Hunnam abruptly and silently quit the movie. His departure was a shock for fans and the studios behind the film, Universal Pictures and Focus Features, blamed the exit on a busy TV schedule.

James told EW that the news was "disappointing" but she truly wishes the actor all the best. Some fans were upset over the news while others hoped it was another chance for the studios to get the casting right... and they did. Almost two weeks after Hunnam quit James announced that "Once Upon a Time" actor Jamie Dornan would be the replacement.

"It's been interesting with Jamie, [the fan reaction] has been so positive," James said.

There was some backlash over the female lead casting - given to actress Dakota Johnson - but the studios have stuck behind their decision. At one point after Hunnam's exit fans were pressuring the film to dump the 24-year-old actress and recast her role too. James and the studios wouldn't budge.  

"She's an old soul, but she's so sweet, and she has a wicked sense of humor," James said about Johnson.

Now that casting the two lead roles are out of the way the movie is finally preparing to begin production in Vancouver at the beginning of December. Recently, the film gave fans a major teaser by releasing character photos of Christian and Anastasia. As for the pressure to get the film right, James admitted that she is "terrified."

"I'm terrified. Completely. I've been terrified from the moment I published the book," she said. "You don't expect this kind of success. Even now it floors me. My only ambition for the books was to see them in bookstores. This is huge. And there is this passionate fandom; we need to get this right for them."