Dakota Johnson, who plays college student-turned-submissive Anastasia Steele in the film based on the best-selling erotic book series, talked to ET special correspondent Jason Dundas about filming the kinky adaptation, admitting that her body was used for all of the film's nude scenes...except for one.
"There was a close up of a bum getting hit with a belt," Johnson says. "That was not my bum, because I didn't want to get hit with a belt."
Johnson's co-star Jamie Dornan was sympathetic to the fact that Steele’s character is much more vulnerable in the film than his millionaire businessman Christian Grey, who pursues the college reporter and entices her into a BDSM relationship.
"For Dakota, especially, she's fairly exposed in those situations," says Dornan. "She's naked, literally being tied up or whatever it is, and that's not easy. It's not a comfortable environment."
Most of the film’s kinkier scenes were unfamiliar territory for the stars, so producers made sure to have an expert on set to help out.
"[The scenes are] really technical and really choreographed because it has to be safe and also done the right way," Johnson tells ET. "There are a lot of rules and things you need to do the right way in order to stay true to the BDSM subculture. We had a consulting dominant who would be on set to help with exactly how to tie knots and where things are placed."
He may have been uncomfortable on set, but Dornan encourages fans to get over the stigma and go see Fifty Shades of Grey when it opens worldwide over Valentine’s Day weekend.
"I think if your girlfriend or your wife asks you to go to that and she wants to see it, you have to give her what she wants," says Dornan. "Like, why wouldn't you go? Also, I think it could be beneficial for you. If you go there with your girlfriend, wife, whatever, and you see that movie and come home and feel a bit charged, you know, things happen."
E.L. James, the author of the best-selling book series and a producer on the film adaptation, scoffs at the notion that audiences will only come to see the movie for the sex.
"That's absolute rubbish!" James protests. "What is it about you media that is sensationalizing the sex in this film? It's a passionate love story. People want to see a love story. It's why the books have taken off, because it's a love story."