3. ROONEY MARA

Movie: The Girl with the Dragon Tattoo (2011)
Arguably, the most talked transformation of 2011, Rooney Mara shed her WASP-y image to embody the tough-yet-troubled Lisbeth Salander for David Fincher's adaptation of the famous Stieg Larsson novel. Mara butchered her long brown hair and dyed it black, pierced her nose and nipples, bleached her eyebrows, learned to ride a motorcycle, barely ate and maintained her pale complexion by staying away from the sun for the role. If you compare her new image to her character in The Social Network just one year ago, Mara is entirely unrecognizable.