“BonTaj Collective Action Fund”
Prospect Park Bandshell, Brooklyn, NY

ANYBODY who believes that ya gotta suffer to sing the blues didn’t see Bonnie Raitt and Taj Mahal join forces Wednesday at the Celebrate Brooklyn! benefit concert in Prospect Park.

They were like siblings from different mothers — both excellent in their individual blues sets and red hot together in the second half of the show.

Just about every song the two played together had a moment that left fans slackjawed, but if you had to pick a single high point, it was when they fired up Taj’s 1972 hit “She Caught the Katy (and Left Me a Mule to Ride).” Red-haired Raitt’s bottleneck slide guitar work gave the duet a slithering quality, and Mahal lent the piece proper train rhythm with huffing blues harp and growled lyrics.

While each is an accomplished musician, what made the night special was their chemistry.

Bonnie Raitt and Taj Mahal performing “Comin’ Home” together with their bands @ Celebrate Brooklyn, Prospect Park Bandshell, Brooklyn, NY 8-12-09

Friends make good music together and Mahal, 67, has been pals with Raitt, 59, since the mid-’60s. They’ve never performed together, but you wouldn’t know it from their playful rapport. Mahal got an onstage back-scratch from Raitt, and later he danced to her guitar work with hips unhinged.

Individually, Raitt was a little better than Mahal, although he did knock down killer version of “Fishin’ Blues” that had the fans on their feet.

Raitt towered twice in her solo set, first during “Angel From Montgomery.” She’s sung this John Prine song for 30 years and has made it her signature: When she sang the opening line, “I am an old woman, named after my mother, my old man is another child grown old,” a cappella, it gave you the shivers. That happened again when she unwrapped her heartbreak ballad “I Can’t Make You Love Me.”

The performances by Raitt and Mahal perfectly illustrated what she told the Brooklyn crowd: “The blues never goes out of style.”

dan.aquilante@nypost.com