Singer Amy Winehouse, who has a long and public history of substance abuse, was found dead in her London apartment Saturday afternoon, according to The Daily Mail.

The "Back to Black" singer's cause of death is so far unconfirmed. She was 27 years old.

Winehouse was last seen Friday night at London club the Roundhouse, according to the Independent. Her 15-year-old goddaughter, Dionne Bromfield, was performing, and Winehouse came onstage to sing "Mama Says" with her. reported that news of Winehouse's death came just hours after a statement announcing a hiatus from performances was posted on the singer's website.

"Amy Winehouse is withdrawing from all scheduled performances," it read. "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 attended rehab in London for a week prior to a disastrous comeback performance last month.

Winehouse's 2006 album "Back to Black" won five Grammys, tying the record for most Grammys won in a single night by a female artist. She has been hailed as a trailblazer for female artists, especially those from the UK.