The 47-year-old filmmaker said despite their differences, the author's presence helped a lot in shaping up the film, according to the Hollywood Reporter.
"It's difficult. When you have an author and an auteur, it's a difficult and challenging relationship. I'm not saying that at times it wasn't helpful, but there were times when it was really, really frustrating," she said.
Starring Dakota Johnson and Jamie Dornan in lead, 'Fifty Shades of Grey' hit theatres on February 13, 2015.