David Bowie, whose groundbreaking music inspired generations during a career spanning six decades, has died at the age of 69 after being diagnosed with cancer.
The cultural pioneer's death in New York on Sunday, following an 18-month illness, was confirmed by his family.
Friends, fans and contemporaries described the Heroes singer as "iconic", a "hero" and "one of the greatest performance artists" in history.
Glastonbury founder Michael Eavis said the star - who played the Somerset festival twice before retiring from live shows in 2006 - said: "He's one of the three greatest in the world, ever - Frank Sinatra, Elvis Presley and David Bowie. There's no one else even close."
Bowie's biographer, Paul Trynka, described the Brixton-raised performer as "someone who redefined pop music" and "a creative force who endured over several decades".
He said: "He will be remembered amongst the greats but not just one of them, as a unique great."
Bowie's death was announced by his family this morning.
His son, film director Duncan Jones, tweeted: "Very sorry and sad to say it's true. I'll be offline for a while. Love to all."
The singer and guitarist - known for hits including Let's Dance, Changes and Under Pressure, died surrounded by his loved ones, a statement on his Facebook page said.
Long-time producer Tony Visconti said the late singer's final album, Blackstar - released two days before his death - was "his parting gift" to the world.
Prophetically, its lead single, Lazarus, opens with the lyrics: "Look up here, I'm in heaven," while the accompanying video shows a bed-bound Bowie playing a man struggling to overcome illness.
Stars from the world of showbiz mourned the loss of the Ashes To Ashes singer as they woke to the news - their grief made more acute by the fact little was known about the extent of his ill-health.
Paying tribute on Twitter, comedian and actor Ricky Gervais, who convinced his long-time idol to star as himself - and ridicule Gervais - in an episode of 2006 sitcom Extras, wrote simply: "I just lost a hero. RIP David Bowie."
Scottish singer-songwriter Midge Ure, on ITV's Good Morning Britain, said: "We are all swimming in his wake, so I don't think you could top, on creativity, and consistent creativity, I don't think you could top, anyone could top, David Bowie in the UK musical history."
On Bowie's illness, Ure said: "I think people within the industry had heard rumours about cancer, we'd heard rumours about him not being well.
"We all knew something was amiss but this is more than just turning on your phone in the morning or turning on the television and finding out that another celebrity has passed on.
"I'm standing here, my hands are shaking, I feel as though I've lost something, I've lost something incredibly important today."
Others summoned Bowie's lyrics in written tributes to mark his passing.
Gladiator actor Russell Crowe, referencing one of Bowie's better known singles which featured on covers album Pin Ups 1973, wrote: "RIP David. I loved your music. I loved you. One of the greatest performance artists to have ever lived."
Friend and collaborator Iggy Pop said on social media: "David's friendship was the light of my life. I never met such a brilliant person. He was the best there is."
Prime Minister David Cameron, whose musical tastes are well documented, led the tributes from the world of politics.
He said: "I grew up listening to and watching the pop genius David Bowie. He was a master of reinvention, who kept getting it right. A huge loss."
The singer released Blackstar - the first of his records not to feature his portrait on the cover - with little promotion, having barely performed in public since falling ill in June 2004.
His last musical appearance on stage is listed as a three-song set at New York's Hammerstein Ballroom in November 2006, in which he played Wild Is The Wind, Fantastic Voyage and Changes. Bowie is believed to have performed in the UK for the final time two years earlier at the 2004 Isle of Wight Festival.
He made a surprise comeback in 2013, after a 10-year break from recording, when he suddenly released a new single on his 66th birthday with an album out weeks later.
The star made a habit of confounding the critics - killing off his most famous alter ego, Ziggy Stardust, at the height of his fame - and reinventing himself in roles including glam rocker, soul singer and hippie songwriter.
Bowie, born David Jones in post-war Brixton, south London, kicked off his music career in the R&B boom of the early 1960s.
In 1969 he made his first appearance in the charts with Space Oddity.
A string of albums followed, before 1972's The Rise And Fall Of Ziggy Stardust And The Spiders From Mars made him an international star.
The 1980s saw him combine his pop career with appearances in films including The Man Who Fell To Earth and Absolute Beginners - as well as a memorable turn as the lead in fantasy Labyrinth.
Bowie married supermodel Iman Abdulmajid in 1992 and the pair had a daughter, Alexandria Zahra Jones. He was married to Angela Bowie between 1970 and 1980.
Soon after news of the star's death broke on his social media accounts, "David Bowie" was the top trending topic on Twitter.
Some radio stations also dedicated segments of their breakfast shows to the performer's music.