Next month Joni Mitchell will headline two concerts at the Hollywood Bowl. Forget Oasis, hers is the miraculous comeback of our times. In 2015 Mitchell, now 80, suffered a brain aneurysm that left her unable to speak or walk. The Canadian-born singer-songwriter had, in any case, been in semi-retirement since her album Shine, in 2007.

When she takes to that stage on October 19 and 20, it will be thanks to a little help from her friends. In 2018 Mitchell met the singer Brandi Carlile after a 75th birthday tribute concert, at which Carlile had duetted on A Case of You with Kris Kristofferson. Over dinner Mitchell mentioned that since she no longer played, the musical instruments in her Bel Air home felt forlornly neglected. Might Carlile be interested, she asked, in putting "together some groups of people to come and play in the living room and drink wine and sing and hang out?" Two weeks later the monthly Joni jams were born.

Those get-togethers in the hills of Bel Air sound truly extraordinary. On the introductory episode of the podcast Legend: The Joni Mitchell Story (BBC Sounds), Jess Wolfe and Holly Laessig of the indie band Lucius describe the experience of entering the labyrinthine Spanish-style villa - always through the kitchen - and emerging via a corridor crammed with Mitchell's artworks into a vaulted-ceilinged room with "orchids everywhere, a beautiful grand piano ... she has her throne there, like a glorified La-Z-Boy".

The guest list, curated by Carlile, must make this one of Hollywood's most exclusive, if relaxed, gatherings. Think Paul McCartney at the kitchen door, crying: "I'm the welcoming committee," Elton John or Herbie Hancock at the piano, Chaka Khan or Dolly Parton offering harmonies and Harry Styles serenading his hostess as she sips her pinot grigio.

In the first episode of the new American podcast The Road to Joni, Taylor Goldsmith of the folk-rock band Dawes recalls being at the 2021 Joni jam where Mitchell played again for the first time since her health scare.

"Kathy Bates [the actress], who's a friend of Joni's, presented Joni with a guitar bought in lockdown. All of us are looking at each other with, like, chills, because she hadn't played since her aneurysm. She immediately detuned it to one of her tunings. The way her fingers flow ... nobody strums a guitar like her."

After playing one chord, Mitchell would have put the electric guitar aside if a friend, Marcie, had not asked if anyone else knew a song in that tuning. Although a newcomer to the gathering, Goldsmith went to sit by Mitchell, tuned his guitar to her tunings "as quick as I could" and started singing a little-known 1990s Mitchell song, Come in from the Cold.

"Then she starts taking over," he recalls. "We were all looking at each other and thinking, 'Woah, she's singing.' That night she sang Both Sides Now for the first time. It was a real turning point." In July 2022, Come in from the Cold was one of the songs performed when Mitchell made a surprise appearance with the Joni jammers at the Newport Jazz Festival.

Even if you are already a committed fan, the six-part Legend: The Joni Mitchell Story, narrated by the American singer Jesca Hoop, offers an engrossingly moving biographical overview of a continually questing musician who has overcome multiple setbacks (childhood polio, accidental pregnancy and putting up her child for adoption, complicated relationships), while never betraying herself artistically. No hagiography either - I was unaware of her mid-1970s blackface experimentations. Last week, at the British Podcast Awards, it won the gold arts and culture award.

The more freewheeling, Americana-immersed The Road to Joni, released on the Sheroes network, is an addendum for the liner-note completists. The presenter Carmel Holt's intention is to undertake a cross-country US road trip, converging on Mitchell's LA shindig next month. Each pitstop involves interviews with musicians under her influence.

The Joni jams and subsequent concerts have not just helped to rehabilitate Mitchell and brought about a renewed appreciation of her oeuvre. They also show a music world where women have the kind of agency and independence for which she had to fight tooth and nail.

A chin-stroking muso purist might balk at Chauntee and Monique Ross of SistaStrings having first encountered Joni through Janet Jackson's 1990s sampling. Now they're part of her troupe. What would they like to thank her for, Holt asks. "Being a badass, quirky woman who showed how to stand on your own and make weird music."