Marianne Faithfull, the singer, actress, steely-eyed “It” girl of Swinging ‘60s London and subject of numerous Rolling Stones songs including “Wild Horses” and “Sister Morphine,” opened her 1994 autobiography with a disclaimer: “Never apologize, never explain — didn’t we always say that? Well, I haven’t and I don’t.”

Faithfull, who once described herself as “the drug-drenched Duchy of Chelsea,” died peacefully in London on Thursday accompanied by her family, a spokesperson confirmed to The Times. She was 78 and previously had been suffering from the long-term effects of a nearly fatal COVID-19 infection in 2020. A cause of death was not revealed.

“She will be dearly missed,” the spokesperson told The Times in a statement.

Faithfull’s unflinching songs, adaptations and roller-coaster life illustrated her unapologetic approach. Described by Irish playwright Frank McGuinness as “interesting … difficult and strange,” Faithfull was descended from Austro-Hungarian aristocrats and first earned fame in 1964, at age 17, with “As Tears Go By,” written by a young Mick Jagger and Keith Richards.

Across 50 years as an artist, she issued solo albums including 1979’s bracing comeback, “Broken English,” 1987’s Hal Willner-produced “Strange Weather” and 2018’s “Negative Capabilities” with Nick Cave and Warren Ellis.

Along the way, she channeled her cigarette-stained rasp to interpret the work of Berthold Brecht and Kurt Weill, Elton John and Bernie Taupin, Tom Waits and Kathleen Brennan, Leonard Cohen, PJ Harvey, Neko Case, Dolly Parton, Morrissey and others.

An artistic force, Faithfull reinvented her musical style with each passing decade, eagerly embracing contemporary sounds and collaborators as engines for her distinctive alto, one that grew more menacing the older she got.

She was a soprano when she met her future boyfriend Jagger at a party in London also attended by Richards, Paul McCartney and Peter Asher. Scouted by Rolling Stones producer Andrew Loog Oldham, Faithfull was in the recording studio with him, Jagger and Richards a few weeks later.

A regular in London’s gossip press of the 1960s, Faithfull was soon at the center of the thriving music and fashion scenes. She sang backing vocals on the Beatles’ “Yellow Submarine” and the Rolling Stones’ “Sympathy for the Devil,” and hung with Bob Dylan during his historic 1965 run of shows in England. In 1967, Faithfull was famously photographed draped in a fur rug during a drug bust at Richards’ estate.

With sharp wit, keen intellect and disarming beauty, Faithfull accessed rooms where millions of Beatles-loving teens longed to be. She wrote in her autobiography of hanging out with Dylan and the Beatles during their peak success: “Jesus, how could I have ever thought these scared little boys were gods?”

Her lineage may have prepared her for the bohemian life. Faithfull was born Dec. 29, 1946, to a mother, Eva, who was a baroness. She descended from a line that included Leopold Baron von Sacher Masoch, who coined the term “masochism” in his erotic book “Venus in Furs.”

Faithfull’s father worked as a spy for British intelligence and was “a truly obsessed eccentric,” she wrote in “Faithfull: An Autobiography.” That ran in the family too. Her paternal grandfather, a sexologist, invented a device called “the frigidity machine,” designed to “unlock the primal libidinal energy” and cure the world’s ills.

After the success of “As Tears Go By” (the Rolling Stones recorded their version a year later), Faithfull continued her recording career and, until 1970, her relationship with Jagger. She characterized those years in her autobiography as: “Desultory intellectual chitchat, drugs, hip aristocrats, languid dilettantes and high naughtiness. I knew I was on my path!”

Most traveled during the 1970s was the path that led to drugs. She described her years homeless and strung out succinctly: “I took the train to London and didn’t return home for years, except for the occasional bath,” she wrote. Anonymous and penniless, she didn’t have a phone or an address. “I was incredibly frail. I never ate. I lost my looks.”

Absent a record contract or musical support, she only made the news as the junkie ex-girlfriend or disgraced aristocrat.

Faithfull got clean in the mid-1970s and returned to upend expectations in 1979 with “Broken English.” Her voice lower from damaged vocal cords, too many cigarettes and other addictions, the album arrived shortly after the British punk explosion, but it wasn’t a punk album per se. It was just hard, unflinching, vulgar, honest.

In addition to the title track, Faithfull transformed John Lennon’s “Working Class Hero” into a feminist anthem and drew wide-eyed attention for “Why’d You Do It,” a harsh, profanity-laden indictment directed at an unfaithful lover. The album earned Faithfull her only Grammy nomination, for female rock vocal performance.

“The Ballad of Lucy Jordan,” from “Broken English,” scored a memorable midnight drive through the desert in the 1991 movie “Thelma and Louise.” Rolling westbound, Susan Sarandon’s Louise plays the Shel Silverstein-penned song on the car stereo, and Faithfull sings of a desperate woman who, at the age of 37, realizes “she’d never ride / through Paris in a sports car/ with the warm wind in her hair” and decides to change the plot.

Though she never earned chart success in the United States, Faithfull was a critics’ darling throughout her career. Her 1987 album, “Strange Weather,” saw her interpreting Bob Dylan’s “I’ll Keep It With Mine,” Leadbelly’s “I Ain’t Goin’ Down to the Well No More” and Dr. John’s “Hello Stranger.”

“Faithfull: An Autobiography” was published in 1994. The first of three memoirs, it recounts her trysts and escapades with humor, brashness and power, and remains an essential music memoir. She issued studio albums at an even pace across the last 25 years of her life, one every few years with a new round of songs and a voice just a little more ragged.

Rock legends Marianne Faithfull, right, with Courtney Love in London in 2021.

(Matthew Lloyd / For The Times)

For her 2008 album, “Easy Come, Easy Go,” Faithfull covered songs by Judee Sill, Randy Newman, Brian Eno and Merle Haggard. Her rendition of Morrissey’s “Dear God, Please Help Me” hits its climax when Faithfull bellows at full volume, “There are explosive kegs / Between my legs / Dear God, please help me.”

The musician had a long, successful career as an actor as well. She performed Chekhov at the Royal Court Theatre, Shakespeare at the Roundhouse and Brecht and Weill at the Gate Theatre in Dublin.

Most famously, Faithfull starred in “The Girl on the Motorcycle,” a sexually charged, LSD-inspired 1968 love story that became one of the first films to be given an X rating by the Motion Picture Assn. of America. She appeared as a vision in “Lucifer Rising,” a notorious 1972 cult film by Kenneth Anger, an experimental filmmaker in Los Angeles. In 2001, Faithfull played God in a memorable series of dream sequences in the British comedy “Absolutely Fabulous” (her longtime best friend, Anita Pallenberg, played the devil).

Faithfull was nominated as best actress at the 2007 European Film Awards for her role in “Irina Palm,” in which she stars as a grandmother who performs anonymous sexual favors to earn money for her grandson’s cancer treatment. In 2011, Faithfull was awarded Commandeur of the Ordre des Arts et des Lettres, one of France’s most esteemed cultural honors.

Her 2018 album, “Negative Capability” was typically adventurous. Teaming in a studio and living space with longtime Nick Cave collaborator Warren Ellis, the album saw her write songs with artists including Cave, Ellis, British songwriter Ed Harcourt and producer Rob Ellis. She told the Guardian that it was “the most honest record I’ve ever made. There are no hidden corners.”

She added, “What a joy, hanging out with those wonderful men.” That, of course, was a setting in which she often found herself, whether she invited it or not.

“My main priority in my head was always my work. But then, of course, the men came,” she explained, “and it wasn’t really what I wanted, but I was too pretty to be left alone.”

In 2021, she released “She Walks in Beauty,” a haunting spoken-word recording of Lord Byron and other British Romantic poets, the backing music — ambient at times — provided by Ellis, Eno, Cave and Vincent Segal. It was her 21st and final album

In her final years Faithfull, who was married three times, had her share of challenges. She broke her back in a fall in 2013 and a year later broke her hip. She was hospitalized for three weeks during the early days of the pandemic in 2020 when she tested positive for COVID 19.

Faithfull is survived by a son, financial writer Nicholas Dunbar, and three grandchildren.

Patti Smith has assured fans that she’s alright after she collapsed on stage in São Paulo, Brazil, on Wednesday night (Jan. 29).

“This is letting everyone know that I am fine,” the legendary 78-year-old singer-songwriter wrote via Instagram on Thursday (Jan. 30), alongside a selfie smiling and waving at the camera. “A grossly exaggerated account is being spread by the press and social media. I had some post migraine dizziness. Had a small incident, left the stage, and returned 10 minutes later and talked to the people, told them I was fine and sang them Wing and Because the night.”

Smith added that after being checked by a medical professional, she was deemed “absolutely fine.” She concluded, “With all the strife in the world, this explainable incident does not merit so much attention. Thank you everyone for your concern. Trust me I am fine.”