NEW YORK, NY.- On Oct. 27, 2022, photojournalist Saiyna Bashir was interviewing musician Michael Brook in his Los Angeles studio when she learned something that prompted an urgent text to Zakir Thaver, her filmmaker colleague in Pakistan:

“New undiscovered album.”

Bashir and Thaver were producing an upcoming documentary called “Ustad” about Nusrat Fateh Ali Khan — the celebrated Pakistani singer who died in 1997 at age 48 — and Brook, the silver-haired musician whose ambient work has crossed paths with Daniel Lanois, Brian Eno and Michael Mann, had just revealed that he was working on an unreleased Khan song.

It was part of “Chain of Light,” an album Brook recorded with Khan at Peter Gabriel’s Real World Studios in England more than three decades ago. “Ya Gaus Ya Meeran,” the track in question, was an unreleased Khan qawwali, a song based on the devotional poetry of Sufism, a mystical branch of Islam.

Khan, a polyglot whose musical family initially dissuaded him from singing in favor of another career, first appeared onstage as a teenager after the death of his father in 1964. Over the next two decades, his music became a balm and source of national pride for Pakistan. He began recording with Gabriel in 1988, and soon appeared on Trent Reznor’s “Natural Born Killers” soundtrack and with Eddie Vedder on the “Dead Man Walking” soundtrack. “Chain of Light” — with four traditional qawwalis written in Urdu, Punjabi and Persian that were recorded in April 1990 — will be released by Real World Records on Friday. (Khan’s daughter, Nida, along with Usha Rajan, the custodian of his estate and a family friend, have both been involved with this project.)

Gabriel, who first encountered Khan when he saw him performing at the WOMAD festival, which he helped found, in 1985, recalled the moment specifically: “It was dusk and you could feel the whole arena becoming charged with the qawwali and that extraordinary, spellbinding voice,” he wrote in an email. Later working with Khan, “I was astonished at his ability to improvise wonderful melodies with all their emotional peaks and troughs,” he added. “He was not just a maestro of the voice but a master composer who could create these classic lines on the fly whilst maintaining a great sense of the whole composition, as it emerged out of the ether for the very first time.”

Oran Mullan, whose job as project manager at Real World involves reintroducing the label’s material to an online audience, discovered the album’s 24-track, 2-inch magnetic tapes during one of his daily scans of warehouse shelves in June 2021. Scribbled across the box was: “Trad Album,” artist: “Nusrat Fateh Ali Khan.”

Mullan initially thought it was one of Khan’s previously released qawwali albums. “The idea that we would find something else seemed unlikely,” he said in a phone interview from England. Mullan and Amanda Jones, the label’s manager, fast-tracked its digitization and sent it to Brook, who had released “Mustt Mustt” (1990) and “Night Song” (1996), with Khan.

“I had no idea how good the quality of the performances would be,” Brook, 73, said in a phone interview from his studio. Nusrat “would just say, ‘Wave in the window when you want us to stop,’ because they could go on for two hours,” he recalled of the sessions.

On “Ya Gaus Ya Meeran,” Khan’s Urdu verses wrestle with dizzying tabla rhythms. The record’s title comes from a refrain about spiritual bonds that traverse generations: “Every breath of mine, is related to his chain of light.” It was written by Pakistani scholar Naseeruddin Naseer Gilani as a tribute to 11th-century Sufi mystic Abdul Qadir Gilani. Rashid Ahmed Din, Khan’s longtime translator and international manager, had suggested Khan record a new qawwali that day. “That song is not commercial, or contemporary,” he said in a phone interview. “It is very traditional.”

Brook said everyone forgot about the extra tracks — “at least I did” — adding, “We just thought it sounded fresh, and a little bit unusual,” referring to Khan’s choice to record an Urdu rarity along with the more popular Punjabi song “Aaj Sik Mitran Di” written by Pir Meher Ali Shah, and “Khabram Raseed Imshab” by Amir Khusrau in Persian.

Khan’s relationship with Brook and Real World came after his ascension, throughout the 1980s, as a bona fide Pakistani celebrity in the diaspora, largely thanks to the Birmingham-based Oriental Star Agencies. The label, which first released Khan’s music outside Pakistan in 1978, was also founded by Muhammed Ayyub, a radio veteran who was one of Khan’s earliest supporters outside the subcontinent.

Ayyub first heard Khan’s “Haq Ali Ali” qawwali in the winter of 1977 in his office. His first reaction: “Oh, what an angelic voice,” Ayyub, 85, said in a phone interview, letting out a soft laugh.

“We had discovered an artist that was out of this world,” he added. “Nusrat lived for music, and the world is benefiting from it today.”

Oriental Star and Khan went on to forge a career-defining bond, resulting in years of tours, hundreds of recordings and multigenerational friendships. Ayyub and Khan’s foresight to record South Asian arrangements with Western instruments and cut traditional qawwalis into tighter edits helped reshape how listeners around the world received Pakistani music. “Why don’t we do something to introduce your voice to the younger generation,” Ayyub remembered asking Khan, who he said would reply, “Yes, why not?”

In 1988, Gabriel introduced Khan to a wider audience via “Passion,” his soundtrack for Martin Scorsese’s “The Last Temptation of Christ.” “Nusrat was singing beside me on the floor of the studio and the amazing Indian violinist L. Shankar was playing from the open balcony just above us,” Gabriel remembered. “They began following my simple melodies and gradually turned up the improvisation and emotion until the dialogue was so intense and alive that everyone in the room knew they were witnessing a unique spiritual moment.”

“The fact that it was a Muslim and a Hindu making music for a film about Christ all disappeared and melted into the magic of that extraordinary moment,” he added.

Bashir and Thaver, who are aiming to premiere their feature-length documentary next year, are still chasing characters from Khan’s life, sourcing obscure performances and looking for a distribution partner.

Combing through 800 hours of footage, they’ve cataloged rapturous crowd moments and assembled revelations from Khan’s globe-trotting years, including details surrounding his deteriorating health shared by his physician and a magnified look at how extensive touring took a toll on his group’s interpersonal relationships.

“People may think he was such a big star, with his Hollywood and Bollywood collaborations, that must’ve made a lot of money, but that wasn’t true,” Bashir said. “He didn’t have the right people who were sensible enough to do the right deals for him.”

How did “Chain of Light” end up sitting untouched for more than 30 years? “Very rarely would there ever be corrections or any rerecording,” Jones said of Khan’s numerous qawwali sessions captured at Real World.

After hearing “Ya Gaus Ya Meeran” for the first time in 32 years, Brook said he “was struck by how harmonically it seemed different than anything I’d heard Nusrat do before.” He was delighted, he added, “that there’s just so much magic in those performances.”

This article originally appeared in The New York Times.