Police said they had found the body of a 27-year-old woman at a home in Camden Square, north London, after being called by ambulance services around 1500 GMT (11 a.m. EDT).
"Inquiries continue into the circumstances of the death at this early stage. It is being treated as unexplained," a police spokesman said. A spokesman for the singer could not immediately confirm she had died.
Police had cordoned off the leafy street outside Winehouse's home in Camden, where around 20 onlookers had already gathered along with media photographers and camera crew.
Winehouse was born on September 14, 1983, to a Jewish family with a history of jazz musicians. She was discovered by soul singer Tyler James at the age of 16 and in 2003 her debut album "Frank" was released, to general acclaim.
Her second album "Back to Black" was released in October 2006 and reached the No. 1 spot.
The album's hit single "Rehab" contained the line: "They tried to make me go to rehab. I said 'no, no, no.'"
What a sad ending for somebody with her talent.
I enjoyed some of her stuff, right before she took the fast track to nowhere.