Bonnie Raitt and Taj Mahal are teaming up for a joint tour in which they perform separate sets before coming together for the grand finale. Called the 'BonTaj Roulet' tour, the 30-date outing aims to raise $1 per ticket sold for charitable causes. Fans can actually vote on which causes in particular via the BonTaj website.

"We've been like ships passing in the night," says Mahal. "Some of my musicians used to play with Bonnie, we have so many of the same friends -- this is really an opportunity to combine some forces and play some great music."

The two blues giants have collaborated before, beginning in the early 1970's when Mahal co-produced Raitt's 'Taking My Time' album, but this will be their first tour together. "It's like we're cousins," says Raitt. "There's going to be a lot of fireworks because it's so fresh." The tour kicks off August 6, and runs through the end of September.