According to The Hollywood Reporter, Mei Melancon has been added to the cast of X-Men 3 as the villain Psylocke, who will battle the X-Men with other members of the Brotherhood of Mutants.  She previously worked with director Brett Ratner (see 'Super-Switch:  Ratner to Helm X3') on Rush Hour 2.  Another star new to the series, Kelsey Grammer, was signed to play Beast last summer.