George Michael — the former Wham! and solo singer whose hit "Last Christmas" is among the holiday season's most inescapable earworms, died Christmas day at age 53, his publicist said.

Police are “treating the death as unexplained but there were no suspicious circumstances.”

According to the BBC report, Michael had previously postponed a series of concerts in 2011 after being taken to hospital for treatment for pneumonia. After treatment, he appeared outside his London home and said whether he lived had been "touch and go," according to that report.

Michael, born Georgios Kyriacos Panayiotou, had a musical career spanning almost four decades.

Michael sold more than 80 million albums worldwide. While in Wham!, the singer scored hits in the early-to-mid ’80s with songs like “Wake Me Up Before You Go-Go,” “Careless Whisper” and “Last Christmas.” He continued to have success in his own right as a solo singer with dozens of hits, including “Faith,” “I Want Your Sex” and “One More Try.”

His iconic debut album, Faith — released 30 years ago in 2017 — won the Album Of The Year GRAMMY Award in 1989.

In 2004, George Michael was named “the most played artist on British radio” by the Radio Academy. “I can’t believe it. I’ve only made six albums in 22 years so I don’t know how this happened. I’m the luckiest writer on earth,” he said at the time.

His sixth and final solo album, Symphonica, was released in March of 2014.

The star's publicist released a statement Sunday: "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 family would ask that their privacy be respected at this difficult and emotional time. There will be no further comment at this stage."

"Last Christmas," written by Michael and recorded by his duo-act Wham!, was released on Epic Records in 1984. The song has been a staple of the holiday season ever since. Spotify reports that in 2013, it was the most streamed single on Christmas Day in the United Kingdom.

— With reporting by the Associated Press and by Bradley Stern of Popcrush