George Michael has died, age 53, BBC and the Press Association report.
He "passed away peacefully at his home," his publicist told the Press Association.
Police say there were no suspicious circumstances, the BBC is reporting.
The star launched his career with Wham in the 1980s and later had a successful solo career.
In a statement supplied to BBC, Michael's publicist said: "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."
The singer nearly died from pneumonia in late 2011. After receiving treatment in a Vienna hospital, he made an appearance outside his London home and said it had been "touch and go" whether he lived.
Doctors had performed a tracheotomy to keep his airways open and he was unconscious for some of his spell in hospital.
Elton John has lead the tributes to the star on social media by posting a heartfelt message along with a picture of the pair together, on his Instagram page.
He wrote: "I am in deep shock. I have lost a beloved friend - the kindest, most generous soul and a brilliant artist. My heart goes out to his family and all of his fans. @GeorgeMichael #RIP"
Ricky Gervais, who cast Michael in an episode of his sitcom Extras, wrote: "Unbelievable. RIP George Michael."
While former footballer Gary Lineker posted: "No, not George Michael as well. Another musical great leaves us this year. 2016 can just sod off. #RIPGeorge."
Electro star Gary Numan tweeted: "Oh no. George Michael RIP."
The official account of eighties pop group Duran Duran also paid their respects by tweeting: '2016 - loss of another talented sould. All our love and sympathy to @GeorgeMichael's family.'
The English singer, songwriter and record producer sold more than 80 million records worldwide.
He had seven No 1 singles in the UK and eight No 1 hits in the Billboard Hot 100 in the US.
Michael was putting the finishing touches to a documentary film 'Freedom', which was to air in March 2017.
It included unseen archive footage from Michael's career.
Stars who died in 2016
Jan 10 - David Bowie (69, UK rock music great)
Jan 14 - Alan Rickman (69, English actor)
Jan 18 - Glenn Frey (67, Eagles founder)
Feb 19 - Harper Lee (89, US author To Kill a Mockingbird)
March 9 - Jon English (66, Australian singer, songwriter, musician and actor)
March 24 - Garry Shandling, (66, US comedian/actor/writer)
March 31 - Ronnie Corbett (85, British comedian and actor (The Two Ronnies)
April 6 - Merle Haggard (79, US country singer-songwriter)
April 21 - Prince (57, US rock musician)
June 3 - Muhammad Ali (74, US boxer, Olympic gold medalist)
July 19 - Garry Marshall (81, US writer/director Pretty Woman, Happy Days)
Aug 29 - Gene Wilder (83, US actor - The Producers, Willy Wonka & the Chocolate Factory)
Sept 25 - Arnold Palmer (87, US golf great) Sept 28 - Max Walker (68, Australian Test cricketer/commentator)
Oct 7 - Ross Higgins (85, Australian TV actor, comedian and voice actor. Best known for his role as Ted Bullpitt in Kingwood Country and Louie The Fly ad)
Nov 7 - Leonard Cohen (82, Canadian singer-songwriter, poet and novelist)
Nov 11 - Robert Vaughn (83, US actor best known for The Man from U.N.C.L.E)
Nov 24 - Florence Henderson (82, US actor who played Carol Brady in the Brady Bunch)
Dec 2 - Andrew Sachs (86, British actor who became a household name as Manuel in the 1970s sitcom Fawlty Towers)
Dec 18 - Zsa Zsa Gabor (99, Hungarian-American actress and socialite)
Dec 24 - Rick Parfitt (68, Status Quo singer/guitarist)
Dec 25 - George Michael (53, British pop superstar)