But Mrs Taylor-Johnson, 47, said that although the film is true to EL James's best-selling book, it may not be as explicit as people might be hoping for.
"The thing that was most difficult was how and where to pepper the sex, and to not make it feel like it was gratuitous," she said.
"So it had to be a really strong part of the story, and I had to give characterisation to each sex scene, to make them different.
"I didn't want it to be graphically explicit, and I know that's going to be disappointing to some people," Taylor-Johnson, who is married to British actor Aaron Taylor-Johnson, 24, added in an interview with The Guardian newspaper:
"It's the build up and titillation of touch and sensuality. So I don't think it goes into the realm of porn."
Asked if he felt he had lived up to EL James's fantasies, Dornan, 32, told the Sunday Times Culture supplement: "Nobody can walk in and embody what she wants. It doesn't exist.
"But I hope I'm the closest thing. I hope I'm a good enough actor, and it's passable."
The father-of-one also said that although the film is sexual, he does not believe it is pornographic or even erotic.
"I just wouldn't use the word 'erotic' - it brings up different ideas for me. I just think we tried to make a good picture, you know?"
Meanwhile, Dornan's co-star Dakota Johnson says she suffered whiplash while making the film.
The 25-year-old actress admitted there were "some painful moments" on set when the pair were acting out some saucy scenes.
She said: "I got whiplash once from him throwing me on the bed; so f****** painful. And I wish we had a gag reel from the shoot. One time we were doing a scene in Christian's kitchen, and I [thought it would be funny] to hide in a cabinet. I pulled the handle, but it was not a real cabinet. The entire set came down on me."
But Johnson admits her injuries helped break the tension on set during intense S&M scenes.
She said: "The fact that I could laugh with [Jamie] was nice. Sometimes I did walk off the set feeling a bit shell-shocked. The drive home from work always helped me snap out of it. And a big glass of wine."
The actress is proud of the film and is looking forward to its release, but doesn't want her family, including mother Melanie Griffith to watch it.
She added to Glamour magazine: "My mum came up for a day [during filming]. She's proud of me. But I don't want my family to see [the movie] because it's inappropriate. Or my brothers' friends who I grew up with."
The series of three Grey books written by James, 51, from London, has reportedly sold more than 100 million copies worldwide and has been translated into 52 languages.
- Daily Mail