Why writing Fifty Shades of Grey film 'broke my heart'

Fifty Shades of Grey stars Dakota Johnson and Jamie Dornan.

Fifty Shades Of Grey screenwriter Kelly Marcel has still not seen the raunchy movie because the creative struggles with EL James throughout the process "broke her heart".

The Saving Mr Banks writer signed on to adapt James' bestselling kinky novel into a movie, but her first draft of the script was rejected by the author and the pair rewrote another draft together which was a "halfway compromise".

Although Marcel has the only writing credit in the film, she actually left the project around the time Charlie Hunnam, the original actor for Christian Grey, departed.

Two male writers were drafted in to make more adjustments, and Marcel remains too upset about the process to watch the final product.

"I have not seen the movie Fifty Shades of Grey," she tells author Bret Easton Ellis in his podcast.

"My heart really was broken by that process, I really mean it, so I don't say it out of any kind of bitterness or anger or anything like that, it's just I don't feel like I can watch it without feeling some pain about, you know, how different it is to what I initially wrote and also how separated ... we were a very tight team in the beginning of that process and it all became very sort of disparate towards the end, so I haven't actually haven't seen it."

Director Sam Taylor-Johnson also implied she had creative differences with James on the project, and Marcel confirms the moviemaker was "handcuffed" and could not fulfil her vision.

She also added: "Ultimately Erika (James) did have all the control. There wasn't ever going to be where the producers or the studio could step in and say 'no, no, we're going with this first draft."'

Neither Taylor-Johnson nor Marcel are returning to work on the sequel, Fifty Shades Darker.

James' husband Niall Leonard is working on the screenplay.

- WENN