Usher, Green Day, Ludacris and Alicia Keys are among the stars who have signed up for a Hurricane Katrina relief concert which will span three cities across America.

Dave Matthews Band, Rob Thomas, Linkin Park's Chester Bennington, David Banner, Gretchen Wilson and John Mellencamp will also take part in the shows, which will be staged in New York, Los Angeles and Nashville on 10 September (05) and air live on US cable networks MTV, VH1 and CMT.

Additional artists are expected to be added to the line-up, and proceeds from the show will go to the American Red Cross.

Meanwhile, Dave Matthews Band have added a fourth date to its sell-out shows at Colorado's famous Red Rocks venue to help the victims of Hurricane Katrina.

The proceeds from the extra show on 12 September (05) will go to benefit hurricane relief charities.

MTV's parent company, Viacom, has also announced that it has contributed $1 million (GBP550,000) to the American Red Cross Disaster Relief Effort.

Hundreds are feared dead and tens of thousands are without shelter in Louisiana, Mississippi and Alabama in the hurricane's wake.