The 22-year-old is said to be the first choice of producers Mike De Luca and Dana Brunetti, who have been put in charge of the movie version of E L James' erotic series, reported Contactmusic.
Watson is said to have the right looks for the part, combining a degree of innocence with the acting skills to portray the young graduate who gets swept into a world of a kinky billionaire, Christian Grey.
Others in the frame to play Anastasia are believed to be Elizabeth Olsen, Mila Kunis and Kristen Stewart.