Green Day, Usher, Alicia Keys to appear.

Green Day, Usher, Alicia Keys, Dave Matthews Band, Rob Thomas, Ludacris, Gretchen Wilson, John Mellencamp and Linkin Park's Chester Bennington are the first acts confirmed to appear at a live performance special set for Sept. 10 on MTV, VH1 and CMT. The event will raise funds via call-in donations for relief in the wake of Hurricane Katrina, which devastated New Orleans and several other Southern cities earlier this week.

Performances will air from New York, Los Angeles, Atlanta and Nashville and will also be broadcast live on MTV2, mtvU and VH1 Classic.