'Fifty Shades of Grey' cast adds Rita Ora

Dec. 3 (UPI) -- Singer Rita Ora joined the cast of Fifty Shades of Grey just as the movie began filming in Vancouver Monday.

They 23-year-old is set to play Christian Grey's adopted sister, Mia, in the big screen adaptation of E.L. James' erotic novel. She announced the news Monday via Twitter.

The film stars Dakota Johnson, 24, as the naive Anastasia Steele and Jamie Dornan, 31, as Grey. Eloise Mumford will play Steele's best friend Kate Kavanaugh while Max Martini will play Grey's bodyguard.

Though the film isn't due in theaters until February 2015, producers are already discussing the possibility of releasing two versions of the movie -- one they expect will get an R rating and a more explicit version that could be rated NC-17.

[People]