Scarlett Johansson, George Clooney and Matt Damon have teamed up with hip-hop duo Mattafix - Marlon Roudette and Preetesh Hirji – for a charity single project timed to coincide with the Global Day for Darfur on Sunday (Sept. 16). The actors give their intoductory speeches to the band's video, which was shot in a refugee camp in Chad, near the border with Darfur. Mick Jagger will also particpate, providing financial support for the video.