Scott Walker, the American singer who attained massive success as a pop star in England before veering off into avante-garde music, has died, according to his label, 4AD. He was 76; no cause or date of death was immediately announced.

“It is with great sadness that we announce the death of Scott Walker,” a post on the label’s website reads. “Scott Walker has been a unique and challenging titan at the forefront of British music: audacious and questioning, he has produced works that dare to explore human vulnerability and the godless darkness encircling it.”

With a deep and resonant voice, Walker first rose to game as the frontman of the Walker Brothers with hits like “The Sun Ain’t Gonna Shine.” He began releasing solo albums in 1967 in a baroque, orchestral style that has influenced countless artists in the years since, ranging from David Bowie and Radiohead to albums as recent as Karen O and Danger Mouse’s “Lux Prima,” released just last week. While his increasingly challenging music cost him many fans, apart from a Walker Brothers reunion in the mid-1970s the singer never looked back, releasing albums that were individual and esoteric by any standard. In recent years he collaborated with artists ranging from arch pop combo Pulp and Seattle drone-metal outfit Sunn O))) to British avant-pop singer Bat for Lashes.

Born Noel Scott Engel in Ohio in 1943, Walker showed talent as a child actor and singer by the late 1950s and received his first major exposure on the television show of American singer Eddie Fisher. Already showing an interest in jazz and beat poetry by his late teens, Walker moved to Los Angeles and began working as a session musician. By the early 1960s he’d joined forces with John Maus, who was already performing as John Walker, and the pair formed the Walker Brothers in 1964, soon teaming up with drummer Gary Leeds; all three lead members took the last name Walker. The group’s second single, “Love Her,” featured Scott on lead vocal and became a minor hit, and a cover of Burt Bacharach and Hal David’s “Make It Easy on Yourself” topped the British charts and reached No. 16 in the U.S. The group became massive stars in mid-1960s England, with “My Ship Is Coming In” and their defining song, “The Sun Ain’t Gonna Shine Anymore,” also reaching No. 1.

Walker soon launched a solo career, with a series of albums in his baroque style called “Scott,” “Scott 2,” “Scott 3” and a compilation of songs from his British TV series all charting high in the U.K. His music grew increasingly avant-garde and during this period showed the influence of Belgian singer Jacques Brel; Walker’s arrangement of Brel’s song “My Death” was later revived by David Bowie.

With his challenging and self-penned “Scott 4” album in 1969, Walker turned his back on fame and pop music almost entirely. Yet after that album’s commercial failure, he struggled creatively in the early 1970s before reuniting the Walker Brothers in 1975 for three albums, one of which produced the U.K. top 10 hit “No Regrets.” Scott Walker’s work on the last of those albums, 1978’s “Nite Flights,” was dark and experimental and pointed in the direction his later work would take.

The reunion faltered, but in the 1980s retrospective interest in his work arose, and in 1984 he released his first solo album in 10 years, “Climate of Hunter,” which continued in the vein of his work on “Nite Flights.” He worked sporadically but consistently over the following decades, with years passing between albums but occasional appearances as collaborations or one-offs for soundtracks.

In 2000, he curated the London South Bank Centre’s annual summer live music festival, Meltdown, where he wrote the music for a performance by the Richard Alston Dance Project. The following year he produced Pulp’s album “We Love Life.” In 2004 he signed with 4AD and released “The Drift” two years later. By this point contemporary music had caught up with his influence and legacy, and he received strong reviews as well as career accolades such as award from Mojo and Q magazine; he received a standing ovation at the latter’s 2003 ceremony. In 2006 a documentary was released, “Scott Walker: 30 Century Man,” that featured interviews with Bowie, Radiohead, Sting and others; in 2008 a tribute concert was staged in London that featured Pulp’s Jarvis Cocker and Blur/Gorillaz vocalist Damon Albarn, among others, performing his songs. He released his most recent solo album “Bish Bosch,” in 2012 and the Sunn O))) collaboration, “Soused,” two years later. In recent years he also composed the scores for the films “The Childhood of a Leader” and “Vox Lux.” In 2017 the BBC staged a tribute to his music at London’s Royal Albert Hall.

According to his label, Walker is survived by partner Beverly, daughter Lee and granddaughter Emmi-Lee.

Radiohead singer Thom Yorke paid tribute to him early Monday. “So very sad to hear that Scott Walker has passed away, he was a huge influence on Radiohead and myself, showing me how i could use my voice and words,” he wrote. “Met him once at Meltdown [festival], such a kind gentle outsider. He will be very missed.”

More to come …