The first national telethon to raise money for victims of the recent deadly floods in Tennessee just got even more star power ... and even more air time. Keith Urban, Martina McBride and Keb 'Mo have been added to the list of performers for GAC's 'Music City Keep on Playin' - A Benefit for Flood Relief,' joining previously-announced performers Brad Paisley, Lady Antebellum, Dierks Bentley, Rodney Atkins, Kellie Pickler, CeCe Winans, Jaci Velasquez, Randy Montana and Will Hoge.

GAC has also recruited 'Desperate Housewives' actor and Nashville native James Denton to co-host the telethon with 'According to Jim' actress (and Brad Paisley's wife) Kimberly Williams-Paisley. Other presenters include GAC's Suzanne Alexander, Nan Kelley, Storme Warren and Bill Cody, as well as the Food Network's Pat and Gina Neely ('Down Home With the Neelys') and the Travel Channel's Adam Richman ('Man v. Food') and Samantha Brown ('Passport to Great Weekends').

Due to this boost in participation, along with an overwhelming demand by the Nashville community, the telethon has been extended to three hours. Celebrities and other volunteers will answer phones during those hours and beyond to collect call-in donations, with all of the money going to the Community Foundation of Middle Tennessee -- an organization that will distribute funds to those in need.

GAC's flood relief telethon will air live from Nashville's historic Ryman Auditorium, Sunday, May 16 at 8:00 PM ET. It will re-air at 11:00 PM and 2:00 AM, with phone lines remaining open. The event will also be carried live on Sirius/XM satellite radio.

Middle Tennessee suffered the worst flood in decades -- perhaps the worst in history, when more than 15 inches of rain pounded the area over a 48 hour period. The damage, now declared a Federal disaster, totals more than $1.5 billion. Thousands of people have lost their homes, most of them without flood insurance to help rebuild.