Get ready to clutch your pearls -- 'Fifty Shades of Grey' screenwriter Kelly Marcel says that the film adaptation will be as raunchy as the book, which means an NC-17 rating, no doubt.

In an interview with The Telegraph, screenwriter Kelly Marcel says fans of  'Fifty Shades of Grey' needn't worry because they're keeping things pretty close to the source material, which means the film will likely earn an NC-17 rating from the MPAA. [Ed. note: What a writer knows about the eventual MPAA rating of a film is suspect at best. But we digress...]

From Marcel:

Well, there is going to be a lot of sex in the film. It will be NC-17. It’s going to be raunchy. We are 100 per cent going there.

'Fifty Shades of Grey' follows a young woman named Anastasia Steele who hooks up with a wealthy businessman with an S&M fetish named Christian Grey, who tries to make her sign a contract filled with rules about their "relationship." The book began its life as 'Twilight' fan-fiction before the author, E.L. James, changed the names and cashed in, selling over 65 million copies of the trilogy worldwide.