Singer Amy Winehouse, 27, has been found dead at her north London home.
A Metropolitan Police spokesman confirmed that a 27-year-old woman had died in Camden and that the cause of death was as yet unexplained.
London Ambulance Service said it had been called to the flat at 1554 BST and sent two vehicles but the woman died.
The troubled singer had a long battle with drink and drugs which overshadowed her recent musical career. She pulled out of a comeback tour last month.
Jeered at gig
Winehouse cancelled the European tour after being jeered at her first gig in Serbia, when she appeared too drunk to perform.
For 90 minutes, she mumbled through parts of songs and at times left the stage - leaving her band to fill in.
She had recently finished a course of alcohol rehabilitation in London and at the time was under strict instructions not to drink.
A section of the road where the singer lived was cordoned off on Saturday evening, as journalists, local residents and fans gathered at the police tapes.
Forensic officers were seen going in and out of the building.
Winehouse had won widespread acclaim with her 2003 debut album, Frank.
But it was 2006's Back to Black which brought her worldwide stardom, winning five Grammy Awards.
Rumours of Winehouse's death began circulating on Twitter on Saturday evening. Among those to comment was singer and actress Kelly Osbourne.
She tweeted: "i cant even breath right now im crying so hard i just lost 1 of my best friends. i love you forever Amy & will never forget the real you!"
Singer and presenter Myleene Klass tweeted: "OMG. Amy Winehouse. Exceptional talent and really nice lady. RIP."
BBC Radio 1 DJ Fearne Cotton wrote: "Can not believe the news. Amy was a special girl. The saddest news."
Daily Telegraph rock critic Neil McCormick said he was "utterly shocked" at her death.
Last appearance
He said she had appeared focused when giving an "incredible performance" for a recent studio recording of a duet with Tony Bennett.
"It's deeply sad. It's the most completely tragic waste of talent that I can remember," he added.
Winehouse made her last public appearance on Wednesday night when she joined her goddaughter Dionne Bromfield on stage at The Roundhouse in Camden.
The singer danced with Bromfield and encouraged the audience to buy her album in the impromptu appearance before leaving the stage.
At the time she pulled out of the tour, her spokesman had said everyone wanted to do everything to "help her return to her best".
