Robert Pattinson was the top choice to play Christian Grey

He has claimed the author behind the erotic novel wanted the former 'Twilight Saga' star to play the lead in the upcoming movie adaptation.

He wrote on Twitter: "Talked to E.L. James at a party over the summer: her first choice for Christian was Rob Pattinson and Matt Bomer was never in the running."

The screenwriter - who penned the script for 'The Canyons' - also said he drunkenly suggested porn star James Deen for the lead role after he impressed in the noir thriller.

He added: "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."

Earlier today, it was confirmed that Charlie Hunnam has been cast in the role.

E.L. James announced in a series of tweets: "Good moaning all. Hold on to your hats ... I am delighted to let you know that the lovely Dakota Johnson has agreed to be our Anastasia in the film adaptation of Fifty ... So... Christian... The gorgeous and talented Charlie Hunnam will be Christian Grey in the film adaptation of Fifty Shades of Grey. (sic)"