When Debbie Davis moved to New Orleans in 1997, fellow vocalist Leigh “Little Queenie” Harris served as her sisterly guide to the local music community.

“Sitting at the bar at Leigh Harris gigs, I met so many people,” Davis recalled recently. “And performing with Leigh taught me so much. She’s part of the reason I do what I do. I was a good singer before I met her, but I wasn’t as good as I am now.

“I owe her debts that I have no prayer of repaying. When I found out she was sick, it was like a hammer to the heart.”

Early this spring, doctors diagnosed Harris, who now lives in North Carolina, with Stage IV breast cancer that had metastasized to her bones, brain, lymph system and liver. “Some days she feels great,” Davis said. “Some days she feels like it couldn’t be worse. Every time I talk to her she is more positive than some people I know who aren’t sick.”

Friends and family have rallied around her. Harris’ sister, Sally, launched a GoFundMe campaign online to help defray the costs of treatment and day-to-day expenses. Davis has organized a benefit concert Thursday at Snug Harbor, dubbed “Gawd Save the Queen,” featuring more than a dozen musicians who have collaborated with Harris. They’ll play songs from her repertoire, which ranged from jazz standards to original material to her signature “My Darling New Orleans,” the song that, years later, closed the first episode of the HBO series “Treme.”

The roster for Thursday’s show includes three former members of the Continental Drifters — Peter Holsapple, Vicki Peterson and Susan Cowsill — guitarists Spencer Bohren, Cranston Clements and Jimmy Robinson, mother and daughter Suzy and Darcy Malone, and Davis and her fellow members of the vocal trio the Pfister Sisters.

“People that know Leigh love her like family, and there’s a lot of us,” Davis said. “This is the least we can do in the face of what she’s going through.”

Harris grew up in Old Metairie. In the late 1970s, while still in her teens, she and keyboardist John Magnie formed Little Queenie & the Percolators. Working the same circuit as the nascent Neville Brothers, playing deep into the night at Tipitina’s, the Dream Palace, Jimmy’s and elsewhere, the Percolators quickly emerged as one of the city’s most promising and popular bands.

Harris, whose vocal prowess and hard-partying ways earned more than a few Janis Joplin comparisons, blew away audiences with her dexterity and range, pixie-like appearance and commanding, sassy stage presence.

The Percolators disbanded in 1982, with only a single 45 rpm recording of “My Darling New Orleans” to their credit. Magnie and guitarist Tommy Malone went on to form the subdudes. Harris continued to sing with an ever-changing roster of collaborators; she was a regular at the New Orleans Jazz & Heritage Festival for years.

Her Mid-City home flooded as a result of Hurricane Katrina’s breached levees. She subsequently settled outside Greensboro, North Carolina; not long afterward, she married musician Rick Ledbetter.

Over the past decade, she has returned to New Orleans for the occasional gig, including a 2007 reunion of Little Queenie & the Percolators. In her absence, her legend and influence endure.

Davis was living in New Jersey when she and a friend made an impromptu visit to New Orleans that coincided with the 1997 Jazz Fest. During the festival, she met Matt Perrine, a bassist and sousaphonist. By September, Davis had moved to New Orleans. By December, she and Perrine were engaged; they got married the following September.

Perrine was playing with Harris at the time. “Matt introduced us. We sat at the bar and had a drink, and by the end of the night, it was like I had known her forever,” Davis said. “She’s the kind of person that everyone who has an encounter with her has a story.”

Davis met keyboardist Josh Paxton, a member of her band the Mesmerizers, via Harris. Harris introduced Davis to Cowsill, now one of her closest friends. When Suzy Malone left the Pfister Sisters, it was Harris who suggested Davis as the replacement.

Over the years, Davis sang alongside Harris at Jazz Fest and elsewhere. “She’s never suffered from an ego that made her think that other talented voices onstage with her would diminish the attention she received,” Davis said.

“It’s easy to forget how deep her influence goes. There wouldn’t have been a subdudes without the Percolators, and there wouldn’t have been a Percolators without Leigh. She was an integral part of New Orleans music at the time. The ripple effect of what happened in those days… the impact of that rock in this body of water has not finished rippling.”

Thursday’s benefit also is a de facto reunion of musicians from a fondly remembered era of New Orleans music.

“It will be like old home week,” Davis said. “We haven’t all seen each other together in 10 years. Just to see each other, it’s worth doing this gig. The only person missing will be Leigh.”

Follow Keith Spera on Twitter, @KeithSpera.