Sinead O’Connor was found “unresponsive” at a home in south-east London on Wednesday, the Metropolitan Police have confirmed.
Officers were called to a residence in Herne Hill on Wednesday morning, a police statement said, adding that her death was not being treated as suspicious.
A police representative said: “Police were called at 11.18hrs on Wednesday, July 26 to reports of an unresponsive woman at a residential address in the SE24 area.
“Officers attended. A 56-year-old woman was pronounced dead at the scene. Next of kin have been notified.
“The death is not being treated as suspicious. A file will be prepared for the coroner.”
No medical cause was given in the death of the singer and an autopsy will be carried out, London Inner South Coroner’s Court later said.
The result of the autopsy may not be available for several weeks, according to a statement on the court website.
Earlier this month, the Dublin native announced on Facebook that she had moved back to London after a 23-year absence where she was planning to finish a new album.
News of her death was announced by her family on Wednesday.
A statement from O’Connor’s family said: “It is with great sadness that we announce the passing of our beloved Sinead.
“Her family and friends are devastated and have requested privacy at this very difficult time.”
Tributes have since poured in for the singer, who was propelled to international stardom in 1990 with her version of the hit ballad Nothing Compares 2 U.
Sinead O'Connor dies at 56 - in pictures
While she was acclaimed for her musical talent, over the years she became well-known for her outspoken social and political views.
She made headlines in 1992 when she tore up a photo of Pope John Paul II on US TV show Saturday Night Live.
The Pretenders star Chrissie Hynde remembered O’Connor as “a one-off and a huge talent”.
Speaking on the Zoe Ball Breakfast Show on BBC Radio 2, she said: “I put together a big concert for Linda McCartney when she died, and Sinead was a part of that, she was such a riot to hang out with.
“She was a good fun person, but she was always angling, stirring it up. She was a real poking-the-hornet’s-nest kind [of person]. Certainly a one-off and a huge talent and all this stuff that you read about.
She added: “She’s in, without question, a better place. She was a tender-hearted person so she will be. Fly on, sweet angel.”
Born Sinead Marie Bernadette O’Connor in Glenageary, Co Dublin, in December 1966, the singer had a difficult childhood.
She released her first critically acclaimed album The Lion And The Cobra in 1987, and her second studio album, I Do Not Want What I Haven’t Got, followed in 1990 and continued the singer’s success in the music world.
In 2018 O'Connor announced that she had converted to Islam and changed her name to Shuhada’ Davitt, later Shuhada Sadaqat.
The singer also spoke openly about suffering from mental health problems and, during an appearance on The Oprah Winfrey Show in 2007, she said she had been diagnosed with bipolar disorder.
She told Winfrey that medication had helped her find more balance but said it was “a work in progress”.
In January 2022, her 17-year-old son Shane was found dead in Dublin after being reported missing two days earlier.