ANAHEIM, Calif. — Documentary filmmaker Bobbi Jo Hart had never heard of Fanny, the first all-female rock band to release an album on a major label, when she stumbled onto a biography of lead guitarist June Millington on the Taylor Guitars website about eight years ago.

“She found it, and she had the same reaction that thousands of people do now: ‘What? How come I never heard of you?’” Millington says, laughing. “She got my number, and she called me right off.”

Hart’s instincts were good because Fanny, the band formed by Millington and her sister Jean Millington with Alice de Buhr and Nickey Barclay, truly was a groundbreaking group.

On five albums released by Reprise Records between 1970 and 1974, they rocked as hard as any of their male rock and roll peers.

They opened for everyone from Chicago and Humble Pie to Jethro Tull and Jeff Beck. Barbra Streisand hired them to back her in the studio on her albums “Stoney End” and “Barbara Joan Streisand.”

On any night at Fanny Hill, the house they all lived in just off the Sunset Strip, musicians from singer-songwriter Bonnie Raitt to Lowell George of Little Feat might be down in the basement jamming with different members of the band.

The documentary film Hart made, “Fanny: The Right To Rock,” includes all of that as well as the long shadow of the band’s influence on female rock bands and musicians who followed. Cherie Currie of the Runaways, Kathy Valentine of the Go-Go’s and Kate Pierson of the B-52’s are among the musicians interviewed in it.

The late David Bowie, who wrote the band a fan letter in the early ’70s — and two decades later in a Rolling Stone interview was still talking about how criminally overlooked they were — would be pleased.

Bowie, it should be noted, dated Jean Millington for a year or so in the mid-’70s, and she later married his guitarist, Earl Slick, with whom she had two kids.

“They’re as important as anybody else who’s ever been, ever; it just wasn’t their time,” Bowie told the magazine. “Revivify Fanny. And I will feel that my work is done.”

“Fanny: The Right To Rock” is now playing in limited theatrical release, and somewhere out there Bowie can rest easy.

June and Jean Millington were born in the Philippines to a Filipina mother and a white father. As children, their family relocated to Sacramento in 1961; by high school, they’d formed their first band with two other girls.

“Our mom was always into it,” June Millington says by video call from her home in Goshen, Massachusetts. “She went behind our dad’s back and went to a music store and signed for our first gear in ’65.

“Our dad was against it because he said, ‘Well, who’s gonna take care of you?’” she says. “In fact, he was right, but we didn’t care. We just wanted to do it.”

Some nights the sisters would sneak out of the house to rehearse with guitarist Addie Lee and drummer Brie Brandt (now Brie Darling).

They’d shimmy down the tree outside their house, says Jean Millington, who played bass, and then start the car by pushing it silently and then popping the clutch once it was far enough from home not to wake their parents.

Eventually, their dad came around and bought an old school bus to retrofit for the girls to drive their gigs in Northern California, first as the Svelts, later as Wild Honey.

“The Bay Area was our happy place,” June Millington says. “We played with Sly and the Family Stone in Lake Tahoe in spring of ’68. By summer, we had reconfigured as Wild Honey. I was going to UC Davis and Brie and Jean got a house in Los Altos.”

In 1969, though, the young women weren’t sure how much longer their musical career would last. Then their manager lined up a showcase audition on an open-mic-style night at the Troubadour in West Hollywood, and the band climbed aboard the bus and headed south.

Things didn’t feel great at the start of the night.

“They told us, ‘Oh, you can only play for what — five minutes? Fifteen minutes, Jean?” June says.

“Yeah, two songs or something,” Jean Millington says by video call from her home in Davis, California.

“It was short, and when we finish with, let’s say three songs, they jumped up on the tables, they were stamping their feet, they were clapping,” June Millington says. “That whole place erupted.

“I remember looking over at Addie and Jean and we felt such a sense of triumph because the audience got it,” she says. “Then the club manager ran up to Jean and said, ‘Play some more! Play some more!’ And she said, ‘Well, you said 15 minutes …’ You know, made him beg just a little bit.

“That was a good moment for us, so we never forgot it.”

The next day, they were packing the bus to head home when Norma Kemper, an assistant to the producer Richard Perry, who had been at the showcase, called to let them know he wanted to hear them.

Perry convinced Reprise Records to sign them. Lee left the group to be replaced by keyboardist and singer Nickey Barclay, and Darling was let go because Perry insisted they be a quartet like the Beatles. The band changed its name from Wild Honey to Fanny, and moved into the home they named Fanny Hill.

Starting in 1970, Fanny recorded and toured almost nonstop. And it wasn’t always, or often, easy. The band faced racism due to the Millingtons’ Filipina heritage, homophobia because June Millington and de Buhr were gay, and sexism from the misogyny of the times in general and the rock world in particular.

Fanny earned the admiration of musicians who heard them. Todd Rundren produced the band’s fourth album, “Mother’s Pride.” Def Leppard singer Joe Elliott, a young teen at the time, still has a flexi-disc by the band that came in a copy of a British music newspaper. (Both musicians are interviewed in the film.)

Commercial success was more difficult — only two singles cracked the Top 40 — and life on the road and in the band grew difficult. In 1973, when the record company asked them to dress more provocatively, June Millington says she was already “falling apart.” That edict was the last straw.

“They wanted us to do T&A, and I mean, we were a rock and roll band,” Jean Millington says. “And to have to start wearing those skimpy costumes, Jean couldn’t take it. She really couldn’t.”

On the screen, June Millington nods: “I felt like an imposter,” she says.

She left Fanny, and not long after de Buhr followed. Guitarist Patti Quatro and Darling replaced them in the band for a fifth album. But the spirit they’d felt together was gone, Jean Millington says, and soon she quit and the band was done.

And that might have been that, until in 2016, at a tribute concert for June Millington in Northampton, Massachusetts, the sisters and Darling reunited to play a few songs. It felt good to be back together, and they decided to make a new album, calling the reformed group Fanny Walked The Earth in part as a joke about their status as dinosaurs of rock and roll, and part to celebrate the trail they’d blazed.

“It felt like no time had elapsed at all from when we were in our teens,” Jean Millington says of the sessions that got underway with Hart and her small crew now shooting footage for the film.

“It felt incredible,” June Millington says. “We realized, ‘Oh my god, we can show people that chicks at 69 can still, like, totally rock it.’ That’s what we wanted to do.”