Pop superstar George Michael has been described as a "beautiful person" and a "kind and generous man" after he was found dead in bed by his partner.
The 53-year-old musician died from suspected heart failure.
His former long-term partner Kenny Goss said he was devastated at the death, which is being treated by police as "unexplained but not suspicious".
Fadi Fawaz, who began seeing Michael following his split from Goss, said he found the star dead when he arrived to wake him ahead of a planned Christmas Day lunch.
He told the Daily Telegraph: "I went round there to wake him up and he was just gone, lying peacefully in bed. We don't know what happened yet.
"Everything had been very complicated recently, but George was looking forward to Christmas, and so was I.
"Now everything is ruined. I want people to remember him the way he was - he was a beautiful person."
Michael officially announced in 2011 that his 15-year relationship with Goss had ended - but said the pair had actually split around two years earlier.
Their relationship was first revealed when Michael came out as gay after being arrested in public toilets in Beverly Hills, California, in 1998 for engaging in a lewd act.
In a statement Goss said: "I'm heartbroken with the news that my dear friend and long-time love George Michael has passed.
"He was a major part of my life and I loved him very, very much. He was an extremely kind and generous man.
"The beautiful memories and music he brought to the world will always be an important part of my life and those who also loved and admired him."
Michael's manager Michael Lippman said it was believed he had died from heart failure, while his publicist said he "passed away peacefully at home".
After his death it emerged Michael had quietly donated millions of pounds to charities, gave a stranger money for IVF treatment and anonymously volunteered at a homeless shelter.
The singer - whose real name was Georgios Kyriacos Panayiotou - sold more than 100 million albums throughout his career.
His death came in a year which has seen the music industry lose some of its biggest stars including Prince, David Bowie and Leonard Cohen.
Michael's former Wham! bandmate Andrew Ridgeley said he was "heartbroken at the loss of my beloved friend Yog", an affectionate nickname used for the star.
He said: "Me, his loved ones, his friends, the world of music, the world at large. 4ever loved. A xx."
Spandau Ballet star Martin Kemp and his wife Shirlie - a backing singer for Wham! with her musical partner Helen "Pepsi" DeMacque as part of the act Pepsi & Shirlie - said they were left devastated.
Kemp previously revealed how Michael was responsible for him getting together with Shirlie, to whom he has been married since 1988.
Their son Roman, Michael's godson, told The Sun the family had planned to go to the singer's house during the Christmas period.
Michael formed Wham! with Ridgeley in 1981, and went on to massive success, releasing a string of hit singles including Wham Rap! (Enjoy What You Do), Club Tropicana and Wake Me Up Before You Go Go.
They were the first Western pop act to visit China when they played there in 1985, before splitting in 1986, by which time Michael had already released a handful of solo singles.
Fans and neighbours gathered at his homes in Highgate, north London and Goring-on-Thames in Oxfordshire to pay tribute to an artist they described as a "huge inspiration".
Michael, whose brushes with the law and tales of drug use saw him hit the headlines, nearly died from pneumonia in late 2011. After receiving treatment in a Vienna hospital, he made a tearful appearance outside his London home and said it had been ''touch and go''.
Michael's 1990 album Listen Without Prejudice Vol. 1 had been set to be reissued accompanied by a new film featuring Stevie Wonder, Sir Elton and the supermodels who starred in the video to his hit single Freedom! '90.
An appeal for archive footage and imagery from fans including "mass Wham! hysteria" was made on Michael's website in August, with a post on his official Facebook page saying: "George is personally seeking rare Wham! & George Michael photos and video and we need your help!"