50 Shades of Grey: Charlie Hunnam, Dakota Johnson star

Charlie Hunnam will play Christian Grey

Actors Dakota Johnson and Charlie Hunnam have been announced to play the leads in the movie version of erotic novel Fifty Shades of Grey.

Johnson will play Anastasia Steele in the film, to be directed by Sam Taylor-Johnson.

British actor Charlie Hunnam, seen most recently in blockbuster Pacific Rim, will play protagonist Christian Grey.

The Fifty Shades trilogy, by author EL James, has sold more than 70 million copies around the world.

Dakota Johnson will play Anastasia Steele

EL James herself announced news on Twitter. She wrote: "I am delighted to let you know that the lovely Dakota Johnson has agreed to be our Anastasia in the film adaptation of Fifty Shades of Grey."

The novels tell the story of the sadomasochistic relationship between billionaire businessman Christian Grey and "unworldly, innocent" literature student Anastasia Steele.

Dakota Johnson is the daughter of actress Melanie Griffith and actor Don Johnson.

She has had small parts in films such as The Social Network and 21 Jump Street as well as TV series Ben and Kate.

Charlie Hunnam appeared in UK drama Queer As Folk and is a main character in US drama Sons of Anarchy.

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