The “Fifty Shades of Grey” movie may have had more drama behind-the-scenes than on screen. Screenwriter Kelly Marcel recently talked to “American Psycho” writer Brett Easton Ellis on his podcast about how involved "Fifty Shades of Grey" author E.L. James was with the film and revealed why director Sam Taylor-Johnson was allegedly feuding with the best-selling author.

Marcel revealed how much control James had over the filmmaking process. Universal had originally accepted Marcel’s plans for a darker script with less dialogue, and she claims they seemed to encourage her changes to the romance novel. “When I delivered that script was when I realized that all of them saying, 'Yeah, absolutely this is what we want!,' and, 'You can write anything you like and get crazy and artistic with it,' that was utter, utter bull----.”

James and Marcel ended up working together to rewrite the “Fifty Shades of Grey” script. While she doesn’t hold any grudges against the author, Marcel revealed that Universal couldn’t stop James from changing whatever she wanted.

“In the end, I think we ended up with a draft that was a halfway compromise, but she had still been very brave about what she had let go,” Marcel said. “And ultimately, [James] did have all of the control so there wasn’t ever going to be a point where the producers of the studio could step in and say ‘No, no we’re going with this first draft.’”

This differs from what Universal executives have previously said. In April, Universal Pictures Chairman Donna Langley said that James didn’t prevent the studio from doing what they wanted. “For the record, the movie we ended up making is exactly the movie I wanted to make and that the studio wanted to make and that our director wanted to make,” Langley said, according to the Hollywood Reporter.

Yet Marcel noted that Taylor-Johnson had to make many changes. Easton Ellis asked Marcel about the fact that the movie -- which starred Jamie Dornan as BDSM-practicing billionaire Christian Grey and Dakota Johson as his submissive, Anastasia Steele -- was largely being made to help sell a brand and merchandise rather than make a great film. Marcel seemed to confirm that this was the reason that Taylor-Johnson allegedly feuded with James and the studio.

“It was clear that there was going to be a struggle,” Marcel said. “It’s very difficult to be a director and be handcuffed in that way and not be able to fulfill your creative vision because there are certain restrictions on you. But at the same time, I would argue that it was very clear that that was the way it was going to be.”

Taylor-Johnson has been vocal about the fact that she and the best-selling author had different creative visions. “We'd often clash and have to find a way to work through that to get to some sort of resolution," Taylor-Johnson told the Hollywood Reporter in February. “She would be the first to say as well that it was not easy. It was not easy. But we got there. I think both of us felt it was an incredibly painful process."

However, Marcel was not on set for the filmmaking process to actually see their feud. She revealed that she left after original Christian Grey actor Charlie Hunnam signed on to the project while more script changes were being made. The writer decided that it was no longer what she intended it to be, and she still hasn’t seem the film.

“My heart really was broken by that process, I really mean it,” she explained. “I don't see it out of any kind of bitterness or anger or anything like that. I just don't feel like I can watch it without feeling some pain about how different it is to what I initially wrote.”

Marcel will not return for the sequel “Fifty Shades Darker." James’ husband Niall Leonard, who is also an author, will write the script. The film is due in theaters in 2017.

Marcel's interview can be heard below: