Fifty Shades of Grey has 20 minutes of sex scenes, meaning it will be the raunchiest mainstream movie for over 10 years. According to the Sunday Times, one-fifth of the film will be made up of sexual scenes - this despite director Sam Taylor-Johnson claiming it was more "romantic".

Fifty Shades of GreyDakota Johnson plays Anastasia Steele in Fifty Shades of Grey

"I think the sex scenes are integral to the story. They are not gratuitous," she added later to Variety.

Last month, the film escaped the most restrictive NC-17 rating from US censors though according to the new report, original author E.L James stepped into persuade Taylor-Johnson to "spice up" the movie. According to the film-nudity site Mr Skin, Fifty Shades of Grey has more sex-scene times than the 100 mainstream 18 (or R) rated films in 2014.

More: Fifty Shades of Grey avoids NC-17 rating - but what does it mean?

The movie stars Jamie Dornan and Dakota Johnson as billionaire Christian Grey and his willing submissive Anastasia Steele. It will be released on Valentine's Day on both sides of the Atlantic. 

Jamie DornanJamie Dornan plays Christian Grey in Fifty Shades of Grey

The original three books in the Fifty Shades of Grey trilogy sold over 100 million copies worldwide and has been translated into over 50 languages. Universal is expected to adapt all three novels for the screen, though this may largely depend on the success of the first film. 

Still, despite the sex scenes - audiences won't see too much of the protagonist. 

"There were contracts in place that said that viewers wouldn't be seeing my ... todger," Dornan told the Guardian. "You want to appeal to as wide an audience as possible without grossing them out. You don't want to make something gratuitous, and ugly, and graphic."

More: Jamie Dornan says filming sex scenes was "not sexy"