This is according to a listing from talent agency GSA music, which says that Zimmer is working on the score for Modern warfare 2.
Call of Duty: Modern Warfare 2 has already caused a stir among people when Activision revealed that the price would be £54.99 in the UK, five pounds more than most releases in the console market.
The game will be released for PC, PS3 and Xbox 360 in November.