Music From the Movies reports that John Powell will compose the music for 20th Century Fox’s X-Men 3:
Powell, whose previous action scores include Face/Off, The Bourne Identity and The Italian Job, is working for the first time with director Brett Ratner. Previous reports about Lalo Schifrin being involved in the project (Ratner worked with him on the two Rush Hour films and After the Sunset) are no longer accurate. The two first X-Men films, directed by Bryan Singer, were scored by Michael Kamen and John Ottman.
You can view Powell’s full filmography here.
Source: Music From the Movies