Billed as "Gary Clark Jr. with special appearance by the Dixie Chicks," Thursday’s Voices for Justice benefit concert at ACL Live was a little bit of a mystery. Would the Chicks play a brief opening set? Would they do something after Clark played? Or might there be a collaboration?


That last possibility was the most intriguing, and indeed turned out to be the case. A little past the halfway point of Clark’s 70-minute performance, he invited Natalie Maines, Emily Strayer and Martie Maguire onstage to join him and his band for what turned out to be a three-song stretch, much to the capacity crowd’s delight.


The Dixie Chicks kicked things off with their Grammy-winning 2006 song "Not Ready to Make Nice," a politics-is-personal tune that fit the occasion. The concert, part of a gala that included a pre-show dinner and auction for those who bought seats at tables on the venue’s floor space, was a fundraiser for Proclaim Justice, a nonprofit "dedicated to winning freedom for inmates who are factually innocent of the crimes for which they were convicted."


RELATED: Our interview with Jason Baldwin of Proclaim Justice


Clark and his band gave instrumental support on the tune to the women, who sang together at stage left with Maines and Strayer on guitars and Maguire on fiddle. Strayer switched to banjo for the two numbers that followed, both from Clark’s catalog. The Chicks’ harmony backing vocals were a perfect match for "When I’m Gone," a Motown-esque soul-pop tune from last year’s "This Land" album. And they reached back to Clark‘s 2015 album "The Story of Sonny Boy Slim" for the gospel-tinged "Church," a fitting finale for the special-guest portion of the set.


This one’s way cool: #DixieChicks singing with #GaryClarkJr on the Motown-esque "When I Get Home" from his Grammy-winning album. #VoicesForJustice benefit at @acllive pic.twitter.com/oNInXLTklP

— Peter Blackstock (@Blackstock360) February 7, 2020

The crowd clearly loved the Chicks’ cameo, but the evening was also special as a welcome-home celebration for Clark, in his first local appearance after winning three Grammys late last month in Los Angeles. Clark played six songs from "This Land" but notably not its incendiary title track, leaning instead toward tunes that showed the range of what he can do — from the reggae vibe of "Feelin’ Like a Million" to the anthemic sociopolitical burner "What About Us" to the punk-fueled "Gotta Get Into Something."


Well-chosen frames for the set were "Bright Lights," the red-hot blues-guitar showcase from his 2012 major-label debut "Blak and Blu," and the Beatles classic "Come Together," which he recorded for the soundtrack to the 2017 superhero film "Justice League." He encouraged the audience to sing along on that one, and they responded in kind, bringing a joyful end to an event that celebrated the notion of coming together for a just cause.