The mother of Amy Winehouse told a British newspaper on Sunday that the sudden death of her 27-year-old daughter was only a matter of time.

The soulful singer-songwriter, who won five Grammys in 2008 and waged a very public battle with drugs and alcohol, died Saturday in her north London home.

Her mother, Janice Winehouse, told The Sunday Mirror that her daughter seemed unwell the day before she died.

"She seemed out of it. But her passing so suddently still hasn't hit me," Janice told the tabloid.

In a statement to the public, the "Back to Black" singer's family said "Our family has been left bereft by the loss of Amy, a wonderful daughter, sister, niece. She leaves a gaping hole in our lives."

Police said Winehouse's death is being treated as "unexplained" and deemed any speculation that she died of a drug overdose as "inappropriate."

A post-mortem is expected to be conducted on Monday or Tuesday.

Winehouse's fans, however, are not waiting to express their grief and sadness.

A mound of flowers and handwritten notes are growing outside the singer's home where the ambulance crew foud her.

"R.I.P. Never Forgotten," read one message.

"It's all right, love. Go now," read another.

And many celebrity fans are also reaching out, offering words of comfort to her family and loved ones.

Actor Russell Brand, who had his own public battles with addiction, published a eulogy to the singer on his website, urging the media and public to change the way addiction is understood -- "not as a crime or a romantic affection but as a disease that will kill."

"Winehouse and I shared an affliction, the disease of addiction," he wrote. "Addiction is a serious disease; it will end with jail, mental institutions or death."

Fellow singer Carole King, whose song "Will you Love Me Tomorrow" was covered by the late singer, remembered the performer's powerful voice.

"She did such a beautiful performance on it," King told the BBC, adding she was grateful to Winehouse for the recording.

"I just really hope that she's found peace now whereever she is," King said.

No information about Winehouse's funeral or burial has been released.

With files the Associated Press