VIDEO : Martina McBride, Kelly Clarkson Unite for Musicians on Call Tour

A trio of powerhouse vocalists are lending their support to Musicians on Call, the non-profit organization that brings live and recorded music to the bedsides of patients in healthcare facilities across the country. When the four-city Rock the Room Tour kicks off October 21st in Nashville, the benefit will feature performances by Martina McBride and Kelly Clarkson, along with a special appearance by Reba and other surprise guests. After its inaugural date in Nashville next month, the Rock the Room Tour will travel to New York, Los Angeles and Washington, D.C., with performers in each location to be announced at a future date.