Jennifer Lawrence, well known as Mystique. Has been in the following movies - X-Men First Class and X-Men Days of the future past. In both movies she plays the part Mystique - a mutant that can change her looks at her will. Jennifer Lawrence is the look of Mystique when she is not blue. When she is in true Mystique form - a blue Mutant - she is stronger than her human form.
In the X-men movies Jennifer is half naked while being the blue Mystique.