Raitt and Mahal will take the stage individually for full sets before finishing each evening's performance with a collaborative closing set. Raitt will perform with her backing band, while Mahal will take the stage with his six-piece Phantom Blues Band.

"There's gonna be a lot of fireworks, because it's so fresh," the Grammy-winning songstress said in a press release. "I think about it before I go to sleep, toying with the possibilities, and it feels like having an extra slice of pie, getting both of these bands to play together like this. There's so much potential to what we can do."

Both artists are socially conscious and plan to raise money with the BonTaj Collective Action Fund, pledging $1 per ticket sold on the US tour to charity. Concertgoers can vote on which cause to support at the tour's website, with proceeds distributed in proportion to the final online tally. VIP packages will also be available, complete with an after-show meet-and-greet and premium seating, with money raised going straight to the Action Fund.

Raitt, who has toured extensively behind 2005's "Souls Alike," postponed eight March dates due to a family health emergency. The southern shows have since been rescheduled for mid- to late October.

Taj Mahal, who will be inducted into the Blues Hall of Fame next month, celebrated his 40th year in the music business with last year's "Maestro," featuring guest appearances by Ben Harper, Jack Johnson, Los Lobos and several others.