George Michael Dead at 53

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Singer George Michael has died at age 53, ET confirms.

The singer died of heart failure in his sleep at his country home in London, England, on Sunday. His manager confirmed that Michael had not been ill.

"It is with great sadness that we can confirm our beloved son, brother and friend George passed away peacefully at home over the Christmas period," his rep told ET.

"The family would ask that their privacy be respected at this difficult and emotional time. There will be no further comment at this stage."

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In a statement, the Thames Valley Police said, "Thames Valley Police were called to a property in Goring-on-Thames shortly before 2pm Christmas Day. Sadly, a 53-year-old man was confirmed deceased at the scene. At this stage the death is being treated as unexplained but not suspicious. A post mortem will be undertaken in due course. There will be no further updates from Thames Valley Police until the post mortem has taken place."

Producer Nile Rodgers tweeted that he had just been at Michael's house this past weekend. "I'm stunned," Rodgers wrote.

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Born Georgios Kyriacos Panayiotou to a Greek immigrant father and British mother, Michael grew up in working class London and went on to sell more than 100 million albums worldwide over a career spanning nearly four decades.

The singer-songwriter was best known for his massive success in the early 1980s as half of the duo Wham!, with Andrew Ridgeley, before his breakout solo hit, "Careless Whisper," led him to pursue a career on his own.

His debut solo album, Faith, sold more than 20 million copies and won Album of the Year at the 1989 GRAMMYs.

Early Sunday night, The Recording Academy released their own statement on Michael's death.

"We are deeply saddened to learn of the passing of two-time GRAMMY® Award recipient George Michael. During an influential career that spanned nearly four decades, George became one of the most beloved pop craftsmen and respected entertainers," the statement read. "From the enormous success he achieved with pop duo Wham! to his influential solo career, his extraordinary talent had a profound impact on countless entertainers worldwide, and his creative contributions will live on forever."

"We have lost a cherished artist and our sincerest condolences go out to George’s family, friends, and musical collaborators," they added. "He will be missed."

According to an update to his official website in November, Michael was "busy putting the finishing touches" on a documentary film titled Freedom.

"He has discovered some incredible, unseen archive footage and is shooting additional interviews for the project," the update said, adding that Michael and Sony Music were planning to reissue his second solo album, Listen Without Prejudice, to coincide with the doc's release in March 2017.

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Wham!'s saccharine sweet pop tunes were huge hits in the UK and beyond, propelling both Michael and Ridgeley into stardom.

But beginning with "I Want Your Sex," his first single off Faith, Michael's songs were clearly made of more adult matter, often sexually explicit and politically controversial. He questioned monogamy, criticized celebrity culture and attacked conservative politicians both at home and abroad.

Michael did not publicly talk about being gay until 1998, after he was arrested in Beverly Hills, California, in a sting operation by police who said he was engaged in a lewd act. (Michael insisted he had been entrapped and later made a music video for his song "Outside" skewering the situation.)

But his sexuality had been the subject of massive speculation for years before that proclamation. Michael, who had told Ridgeley he was bisexual when he was 19, later said he had dated and slept with both men and women during the Wham! years.

He fell in love with a Brazilian fashion designer, Anselmo Feleppa, in 1991, who died from AIDS two years later, and then had a longtime relationship with an American businessman, Kenny Goss, until the two separated more than a decade later, in 2009.

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His debut solo album, Faith, sold more than 20 million copies and won Album of the Year at the 1989 GRAMMYs. He also scored MTV's Video Vanguard tribute that year.

The 1990 followup, Listen Without Prejudice Vol. 1, was launched by its biggest hit, "Freedom '90," -- even though Michael, who was battling Sony Music at the time, didn't even appear in the music video, which was directed by David Fincher. Instead, supermodels including Linda Evangelista, Cindy Crawford, Christy Turlington and Naomi Campbell lip synced the lyrics.

But after his sophomore album, Michael retreated significantly from the spotlight, and though his work continued to chart and sell well internationally, his fame in the U.S. began to fade.

He grieved the death of his partner on 1997's grief-stricken disc, Older, whose songs were steeped in a loss that he didn't clearly acknowledge the impact of until years later. He put out two greatest hits albums, Ladies & Gentlemen and later Twenty Five, but didn't tour for 15 years, only returning to the stage in 2006 for an 80-city world tour.

Michael's duets were diverse, from the No. 1 single "Don't Let the Sun Go Down On Me" with Elton John to R&B tracks that paired him with Aretha Franklin, Whitney Houston and Mary J. Blige, and he released an album of covers, Songs From the Last Century, in 1999. His final album, Symphonica, mostly live recordings of his older songs and standards, was released in 2014.

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Michael was an avid and unapologetic marijuana user for many years, but in 2006 he was arrested on suspicion of possession of drugs after being found slumped over the wheel of his car in the middle of a road. It was the first in a series of drug and auto-related incidents, culminating in a four-month stint jail followed by rehab.

In 2011, he canceled a performance when he was hospitalized for pneumonia, and in 2013 spent two weeks recovering in a hospital after falling out of a car and badly injuring his head.