Fifty Shades Of Grey author EL James has revealed she is "terrified" about the upcoming film based on her book.
Dakota Johnson and Jamie Dornan are set to play the film's leads - kinky businessman Christian Grey and his girlfriend Anastasia Steele - in Sam Taylor-Wood's big-screen adaptation of the novel, but the writer feels under pressure to satisfy the fans.
"I'm terrified. Completely. I've been terrified from the moment I published the book," she told Entertainment Weekly.
"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."
She admitted that the fans would blame her if they didn't like the movie, adding: "Of course they will. They hold me responsible for everything."
EL - the pen name of Erika Leonard - admitted she had initial doubts about taking her book to the big screen.
"I didn't know if it was the right thing to do. And then I thought, 'I'm middle-aged; when in the hell am I going to get another chance to make a movie in Hollywood?' That was the final thing: Let's go for it. Let's see if we can have some fun with it," she said.
The author said she approves of the casting of Dakota and Jamie, who took over after Charlie Hunnam dropped out, citing his busy schedule and family conflicts.
"She's an old soul, but she's so sweet, and she has a wicked sense of humour. It's been interesting with Jamie, the fan reaction has been so positive," she said.
The Fifty Shades Of Grey film, originally scheduled for released in August 2014, will now be released on February 13, 2015.