In a statement, the London Metropolitan Police said, "Police were called by London Ambulance Service to an address in Camden Square NW1 shortly before 16.05hrs today, Saturday 23 July, following reports of a woman found deceased. On arrival officers found the body of a 27-year-old female who was pronounced dead at the scene. Enquiries continue into the circumstances of the death. At this early stage it is being treated as unexplained."
A suspected drug overdose took the life of the singer, Nick Buckley of the Sunday Mirror tweeted.
She's battled drug addiction for years, having most recently checked back into rehabilitation in May.
Winehouse entered treatment in late 2007 for drug problems, including admitted heroin use.
Earlier in the day, Tim Gatt of Sky News tweeted a statement from her manager saying that she was canceling upcoming performances, writing, "Amy Winehouse is withdrawing from all scheduled performances. Everyone involved wishes to do everything they can to help her return to her best and she will be given as long as it takes for this to happen."
She performed in a surprise appearance at the iTunes Festival on July 20th.
Winehouse has had previous near-death experiences, including one her ex-husband, Blake Fielder-Civil, described in detail back in 2009.
"I knelt over her as she kept on fitting. But then suddenly she just passed out and stopped breathing," he told The Sun (via NME). It was the most frightening thing I had ever seen. I felt sure I was watching her die right in front of me. I didn't know what to do or how to save her. I held her to me - and I thought she was dying in my arms. But somehow I managed to open her mouth and breathe air down her throat."
In January, 2010, she pled guilty to assaulting a theater stage manager.
In 2008, after some confusion, a spokesperson for Winehouse confirmed that she had "early signs of what could lead to emphysema."
UPDATE: Sky News Home Affairs Correspondent Mark White reports that sources confirmed that Winehouse died of a drug overdose.
UPDATE II: In a statement to Just Jared, Monte and Avery Lipman, heads of Universal Republic Records, said: "We are deeply saddened at the sudden loss of such a gifted musician, artist and performer. Our prayers go out to Amy's family, friends and fans at this difficult time."
UPDATE III: Scotland Yard told RadarOnline.com that an autopsy on Winehouse will be performed on Sunday.
"The postmortem has not been scheduled yet but it is unlikely to take place before tomorrow. In the case of a murder it can be done within hours but this is not the case so tomorrow or even Monday is more likely in these circumstances."
UPDATE IV: Winehouse is one of a curiously high number of prominent artists to pass away at age 27. Here's a list of a number of those stars, including Kurt Cobain, Jimi Hendrix, Jim Morrison and Janis Joplin.
UPDATE V: Winehouse's spokesman, Chris Goodman, said in a statement (via Buckley): "Everyone who was involved with Amy is shocked and devastated."
UPDATE VI: Tony Bennett, who recorded the classic pop standard "Body And Soul," with Winehouse at Abbey Road Studios in London this past March, released a statement to HuffPost and Spinner:
"Amy Winehouse was an artist of immense proportions and I am deeply saddened to learn of her tragic passing. She was an extraordinary musician with a rare intuition as a vocalist and I am truly devastated that her exceptional talent has come to such an early end. She was a lovely and intelligent person and when we recorded together she gave a soulful and extraordinary performance. I was honored to have the opportunity to sing with her. It had been my sincere hope that she would be able to overcome the issues she was battling and I send my deepest sympathy to her father Mitchell, her entire family and all of those who loved her."
UPDATE VII: Winehouse's father, Mitch, was en route to New York City for a performance when the death was announced; now that he's learned of the news, he's headed back to London, TMZ reports.
UPDATE VIII: The Sunday Mirror will report tomorrow that Winehouse's death was caused by alcohol and the drug ecstasy.
UPDATE IX: TMZ relays a statement from Superintendent Raj Kohli of the Metropolitan police, saying, "Next of kin have been informed, and I can confirm that officers are now satisfied that the deceased is Amy Winehouse... I am aware of reports suggesting this death is the result of a suspected drugs overdose, but I would like to re-emphasize that no post-mortem examination has yet taken place and it would be inappropriate to speculate on the cause of death."
UPDATE X: Perez Hilton reports that insiders told him that drugs were not likely an immediate factor in Winehouse's death, though alcohol may have been.
UPDATE XI: Goodman, Winehouse's friend and rep, said in a statement that the late singer was found in bed by her bodyguard. "She was in her bedroom after saying she wanted to sleep and when he went to wake her he found she wasn't breathing," he said (via TMZ). "He called the emergency services straight away. He was very shocked. At this stage no one knows how she died. She died alone in bed."
UPDATE XII: Sky News' Mark White tweets: "The Post Mortem into death of [Amy Winehouse] due to be carried out this afternoon at St Pancras Mortuary in tandem with inquest nearby," meaning an autopsy will take place Monday.
UPDATE XIII: Winehouse's family and friends showed up at her home earlier on Monday, paying an emotional visit to the place where she spent her last, troubled hours and thanking fans for their vigils and makeshift memorial to their daughter.
UPDATE XIV: Police sources tell People.com that no drug paraphernalia or signs of usage were found in Winehouse's home, and relays a report that claims she told bodyguards she was going to sleep hours before being found dead in her bed. Police say there was nothing "suspicious" about her death.
UPDATE XV: Winehouse's funeral will take place on Tuesday, it was announced on Monday.