Adds further quotes, details (first version posted at 21:34)
Amy Winehouse has been found dead in her London apartment, Press Association (PA) news agency reported Saturday, citing sources.
The 27-year-old was found by the emergency services. Her death was reportedly being treated as "unexplained", dpa reported.
PA reported that the London Ambulance Service said it was called to the flat in Camden Square at 3.54 pm (1454 GMT). Two ambulance crews arrived at the scene within five minutes and a cycle responder also attended, according to a spokeswoman.
"Sadly the patient had died," she added.
The singer had cancelled all her tour dates and engagements last month after a series of erratic public appearances.
Winehouse had been troubled by drink and drugs problems throughout her career.
She last was seen in public just Wednesday night in an impromptu appearance in joining her goddaughter Dionne Bromfield on stage at The Roundhouse in Camden. Winehouse danced with Bromfield and encouraged the audience to buy her album before leaving the stage.
PA reported tributes immediately pouring in from fellow celebrities via Twitter over Winehouse's death, including singer-actress Kelly Osbourne, singer LeAnn Rimes, television presenter Piers Morgan and Sarah Brown, the wife of former prime minister Gordon Brown.
"I cant even breath right now im crying so hard i just lost 1 of my best friends," the Osbourne message said. "I love you forever Amy & will never forget the real you!"