LONDON - George Michael's boyfriend broke his silence about his death, saying that he found the singer dead in bed on Christmas morning.

Australian celebrity hairstylist Fadi Fawaz, 43, revealed this on Twitter on Monday, calling Michael his "partner".

He wrote: " Its a xmas i will never forget finding your partner dead peacefully in bed first thing in the morning.. I will never stop missing you xx."

Michael had died unexpectedly of heart failure, his manager Michael Lippman told Billboard on Sunday afternoon.

He said he received a call that morning notifying him that Michael had been found "in bed, lying peacefully" at his home in Goring in Oxfordshire, England.

The singer-songwriter was 53.

British police said the death was "unexplained but not suspicious".

In an interview with The Daily Telegraph, Fawaz, who had been in a relationship with the star since 2011, said he had gone to Michael's house as they were supposed to go for a Christmas lunch together.

"I went round there to wake him up and he was just gone, lying peacefully in bed," he was quoted as saying in the report published online on Monday.

"We don't know what happened yet. Everything had been very complicated recently, but George was looking forward to Christmas, and so was I."

The newspaper also cited an unnamed source as saying Michael had a heroin addiction, and that he had received hospital treatment for an overdose.

Michael apparently had been preparing to celebrate Christmas, according to reports.

He had decorated his garden with Christmas lights, and a neighbour mentioned seeing Christmas deliveries arriving, though no guests were sighted.