Fifty Shades of Grey won't be another Twilight
The books, about a torrid love affair between a college student, Anastasia Steele, and mysterious billionaire, 27-year-old Christian Grey, have been translated into 45 languages worldwide, selling more than 32 million copies in e-book and print in the US.
E L James, Fifty Shades... author (Credit: Wenn)
Universal and Focus snapped up the film rights for $5 million in March 2011 after a heated Hollywood bidding war.
The movie, which will be rated NC-17 (18 in the UK) is being co-produced by Dana Brunetti, who brought us 'The Social Network' and James herself.
Marcel, 38, the co-creator of Steven Spielberg's US sci-fi TV series Terra Nova, believes the book is a "modern love story involving two complex characters" and that she feels "very deeply" for Christian.
The script is being very closely guarded. "There are shredders arriving at my house at this moment because in LA my trash was gone through."
Although casting rumours are rife, Marcel insists no actors will sign up until there is a finished script.
Marcel recently wrote the script for Saving Mr Banks, about Disney's 20-year pursuit of the film rights to Mary Poppins, starring Emma Thompson and Tom Hanks. She also did the rewrite on 'Bronson' with British actor Tom Hardy, who wears a tattoo on his upper arm "Skribe" dedicated to Marcel (the "K" is for Kelly).