Hunnam is the blond British actor who stars as a tough but conflicted American biker in "Sons of Anarchy." Dakota Johnson, the daughter of Hollywood heavyweights Melanie Griffith and Don Johnson, is the flaxen-haired starlet who has been a bright spot in the films "21 Jump Street" and "The Five-Year Engagement," and a star of the charming, gone-too-soon TV show "Ben and Kate."
The two will play, respectively, billionaire Christian Grey and naive college student Anastasia Steele in an adaptation that's looking a little like Fifty Shades of Blond.
Author Brett Easton Ellis, who waged an unsuccessful public Twitter campaign to write the "Fifty Shades of Grey" screenplay, had his own take on the casting.
He tweeted that he talked to James over the summer -- "at Rob Pattinson's house" -- and the "Twilight" series star was her first choice for Grey. Then Ellis, who may have been joking, tweeted, "When E.L. James asked me who I thought should be Christian I said 'James Deen, of course' and then she shoved me. We were both very wasted."
James is a producer on the "Fifty Shades of Grey" film, which is to be released by Focus Features in August 2014. Sam Taylor-Johnson is to direct from a script by "Saving Mr. Banks" screenwriter Kelly Marcel.
The book and its sequels, "Fifty Shades Darker" and "Fifty Shades Freed," have sold 70 million copies.