'Fifty Shades of Grey' Release Date News: Director Admits Frustration With Book Author E.L. James

"Fifty Shades of Grey" director Sam Taylor-Johnson has revealed that he found it very challenging to work closely with the author of the best-selling erotic novel in making the film.

The 47-year-old filmmaker admitted that the presence of "Fifty Shades of Grey" author E.L. James helped a lot in shaping up the erotic romance, which will premiere a day before Valentine's Day.

"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," Taylor-Johnson said, according to Hollywood Reporter.

"But there were times when it was really, really frustrating," she added.

Taylor-Johnson is as wide-eyed innocent as the erotic novel's Anastasia Steele since she had only directed a 2009 indie feature, "Nowhere Boy," before being hired to direct the much-awaited big screen adaptation of "Fifty Shades of Grey."

But while exploring the world of bondage and discipline, sadism and masochism, she said she was able to endure the daily battle with the book's highly opinionated author.

Last week, it was revealed that James will literally have the last word in what kind of ending the movie will treat moviegoers instead of the ending preferred by Taylor-Johnson.

Universal granted James, whose real name is Erika Leonard, with exceptional control after the studio bought the rights to the material for a reported $5 million in a frenzied auction in March 2012.

As anyone who's read the books knows, the first volume ends after Anastasia (played by Dakota Johnson) asked Christian Grey (Jamie Dornan) to give her a good shellacking.

When Christian obliged, Anastasia recoiled and left him with the final word in the film "stop."

But in the ending favored by the director and mother of four, the last word in the movie was "red," which is used in the trilogy as a "safe word."