R&B legend/Rock and Roll Hall of Famer Mavis Staples and singer Joan Osborne kicked off their “Solid Soul Tour” at the Fillmore in San Francisco on September 25th. Osborne started the night off with a a solo set before being joined onstage by Staples, and eventually the two were joined by a surprise guest: blues/country legend Bonnie Raitt. Check out the gallery below: