George Michael, the British singer who rocketed to fame in the 1980s duo Wham! before embarking on a phenomenally successful solo career, died at 53, his publicist confirmed.

“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,” the publicist said in a statement. “The family would ask their privacy be respected at this difficult and emotional time. There will be no further comment at this stage.”

No cause of death was immediately known. The Thames Valley police said that they were called to a property early in the afternoon on Sunday, where a 53-year-old man was confirmed deceased. “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,” the police said in a statement.

Michael was an international pop icon in the 1980s who then became an even more successful solo act. He first found stardom with Wham!, the group that he formed with Andrew Ridgeley and that was responsible for infectious hits such as “Wake Me Up Before You Go-Go” and “Careless Whisper.”

The popularity of Wham! coincided with the beginnings of MTV, and Michael’s easy stage manner and sex appeal earned him legions of fans far beyond the United Kingdom. The duo broke up in 1986, five years after they burst onto the scene, and Michael’s solo work far surpassed the dominance of his pop group.

The London-born singer sold more than 100 million albums, including his 1987 solo debut, titled “Faith,” which sold 20 million copies; the title track became a gigantic hit. In his solo years, he became known as a more serious singer who had other smash songs such as “Father Figure” and “I Want Your Sex.”

“Michael’s post-Wham! solo debut, ‘Faith,’ offered a blueprint for future generations of boy band singers looking for a way out,” critic Allison Stewart wrote in The Washington Post in 2011, just as “Faith” was re-released. “The granddaddy of blue-eyed soul-pop discs, most of it has aged remarkably well, even the parts that were already awkward in 1987: The title track is pure, perfect pop; ‘I Want Your Sex,’ faintly ridiculous then, really ridiculous now, is still completely irresistible. Everything else is either as great (‘Father Figure’) or as wince-inducing (‘Monkey’) as you remember it.”

In 1998, Michael publicly came out as gay in an interview with CNN, a week after he was arrested for “investigation of misdemeanor lewd conduct” in a park restroom.

“I don’t feel any shame. I feel stupid and I feel reckless and weak for having allowed my sexuality to be exposed this way. But I don’t feel any shame whatsoever,” he told CNN, adding, “I want to say that I have no problem with people knowing that I’m in a relationship with a man right now. I have not been in a relationship with a woman for almost 10 years.”

Michael’s legal troubles continued throughout the years, as he was arrested for driving under the influence in 2007 and on charges of drug possession in 2008; in 2010, he was sentenced to prison after another drunken driving charge and possession of marijuana. He called his four weeks in jail “horrific” and vowed to get help, according to the Daily Mail: “It shook me out of my denial in a way that the others hadn’t.”

In the music world, Michael had been out of the spotlight for the past several years, save for an album in 2014 called “Symphonica,” which included live versions of his songs. He made occasional TV appearances, including on the first version of James Corden’s now-famous “Carpool Karaoke” sketch in 2011, as a skit for the Comic Relief charity:

In late 2011, Michael had a life-threatening bout of pneumonia that made it difficult to tour. “I’m a new man,” he told the British media after he recovered, adding, “I have an amazing, amazing life, and if I wasn’t spiritual enough before the last four, five weeks then I certainly am now.”

As news of Michael’s death broke, tributes started pouring in.

On Sunday, the Recording Academy said in a statement: “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. 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.”