Alex Higgins, the former world snooker champion from Northern Ireland, has died after a long battle with throat cancer.
The 61-year-old former world champion was known as 'the Hurricane' by his many fans.
Snooker promoter Barry Hearn said Higgins would be remembered as the "original people's champion" and the man who transformed the popularity of the sport.
Mr Hearn said: "I have known him for nearly 40 years. He was the major reason for snooker's popularity in the early days.
"He was controversial at times, but he always played the game in the right spirit.
"We will miss him - he was the original people's champion."
Higgins, from Northern Ireland, was diagnosed with throat cancer more than 10 years ago.
Higgins was discovered at a block of flats in the centre of Belfast. He had been unwell for some time.
The player had not been answering his mobile phone and the flat had to be broken into, sources close to him said.
A spokesman for the Northern Ireland Ambulance Service said: "We were called to the scene just before 5pm and he was dead when we arrived.
"He was found dead in bed by someone but they don't know how long he was lying there."
Living in sheltered housing on the Donegall Road in Belfast, he played occasionally at the Windsor Snooker Club in south Belfast.
Staff member at the club Toby Tauley said he kept himself to himself but he added he still displayed some of his old magic.
"He played in here one night and he hit a hundred odd break. That is going back a few years," he said.
He said the last time he was in was several months ago.
Higgins is considered to be one of the finest snooker players of all time. He has had long-term problems with alcohol and smoking since winning the world title in 1972 and 1982.
Despite his numerous fights and rows with referees over the years, he continued to play the game regularly and appeared at the Irish Professional Championship in 2005 and 2006.
Higgins has been an inspiration for many of today's best players, including Ken Doherty, Jimmy White and Ronnie O'Sullivan.
Minister for Sport Hugh Robertson said: "Alex Higgins was a colourful character and one of the most popular players of his generation.
"He will be greatly missed by snooker fans and the wider sporting public.
"Our thoughts are with his family and friends at this difficult time."
Former snooker champion and commentator Dennis Taylor told the BBC: "I don't think you'll ever, ever see another player in the game of snooker like the great Alex Higgins."
And he said he had enjoyed some "terrific battles" against the sportsman, adding: "He was a very, very exciting player to watch. He just was totally unique."
Though Higgins "didn't look very well" towards the end of his life, he insisted: "He battled right to the end, did Alex, and that's what he did throughout his whole snooker career."
Steve Davis played a number of classic matches against Higgins in the 1980s.
Tonight he described his former rival as one of the few "geniuses" around the table.
Davis said: "To people in the game he was a constant source of argument, he was a rebel. But to the wider public he was a breath of fresh air that drew them in to the game.
"He was an inspiration to my generation to take the game up. I do not think his contribution to snooker can be underestimated."
As to his own encounters with Higgins around the table, Davis said: "He was quite a fierce competitor, he lived and breathed the game, very much a fighter on the table.
"It was a love/hate relationship with Alex Higgins. The thrill of playing him was fantastic, but the crowd that came along were not your usual crowd. They were much more noisy and you had to play the crowd as well. To many people in the 1980s he was the only player they came to watch."
"I used to be quite frightened of him as an individual, he could be quite vexatious. But on the snooker table, my admiration was immense."
Davis added: "No one player has ever been bigger than the game. But he brought a genius quality that possibly hadn't been seen before.
"He was one of two or three people I would put the word 'genius' to when it came to the table."
Sean Boru, who ghosted Higgins' autobiography, described the snooker star as a troubled soul.
"Everybody who knew Alex knew that this was an inevitability, but it's still a shock when it happens," he said.
Mr Boru leased a flat in Dublin during 2006 and Alex would visit him to work on the book.
"The problem with Alex was that he knew he was a great talent but he didn't quite know how to work it," Mr Boru said.
"Alex was a frustrated genius. He had so much talent but he had very little outreach for it. He believed in himself a lot, but he also doubted himself a lot as well."
Mr Boru said Alex always had difficulties handling fame.
"He never really fully got the gist of the fame-game."
Mr Boru said Alex was always "difficult" as a person but said that once you knew him you could work his personality.
"If you knew how to work Alex it didn't make any difference," he said.
Higgins, who was born in Belfast on March 19 1949, started playing snooker at the age of 11 and won the All-Ireland and Northern Ireland amateur snooker championships in 1968.
After turning professional he became the youngest World Championship winner at his first attempt, beating John Spencer in 1972.
His record was beaten when 21-year-old Stephen Hendry claimed the trophy in 1990.
Higgins missed out on the glory in World Championship finals in 1976 and 1980 but claimed the title for a second time in 1982.
He was banned from five tournaments and fined £12,000 in 1986 when he headbutted UK Championship tournament director Paul Hatherell.
In 1990 Higgins threatened to have fellow player Dennis Taylor shot and he was banned for the rest of the season after he punched a tournament director at the World Championship.
Higgins underwent surgery to remove cancer from his throat in 1998.
'The Hurricane' played snooker with a style and verve never before seen and won the World Championship in 1972, beating John Spencer in the final and again in 1982.
Until the robotic Stephen Hendry turned up as a 21-year-old world snooker champion in 1990, Alex "Hurricane" Higgins had been the youngest ever winner of the title, when he beat John Spencer in the best-of-73-frames 1972 final.
It was Higgins' first appearance at the tournament and his flamboyant style and break-neck speed around the table earned him the "Hurricane" sobriquet. It is a nickname that could just as easily have applied to his life away from the beize, although the notoriously sedate snooker arena also witnessed its fair share of storms.
Higgins' win over Jimmy White in the semi-final was regarded as one of the all time great matches, particularly the Belfast cueman's 69 break in the penultimate frame on the way to a 16-15 victory.
The Hurricane is almost as well known for his off-the-table bust-ups and his many run-ins with snooker officialdom over the years.
At the 1986 UK championships, Higgins was fined and disqualified for head-butting a referee. Four years later, after a first round defeat at The Crucible, Higgins punched a tournament official before going on to announce his retirement from the game.
But despite his difficulties, he remains one of the most gifted players ever to pick up a cue, with Ronnie O'Sullivan the only current star worthy of a mention in the same breath.
Video interview by David Ferrarotto
1949 - March 19 - Born in Belfast, Northern Ireland.
1960 - Starts playing snooker at the age of 11.
1963 - Leaves Northern Ireland to begin a career as a jockey in England, but is released having never ridden in public and returns to Belfast.
1968 - Wins the All-Ireland and Northern Ireland amateur snooker championships.
1972 - After turning professional he wins the World Championship at the first attempt, he beats John Spencer 37-32 in the final. It makes him the youngest winner of the title, a record only beaten by a 21-year-old Stephen Hendry in 1990.
1976 - Reaches a second World Championship final but loses to Ray Reardon 27-16.
1978 - Wins The Masters for the first time as he beats Cliff Thorburn 7-5.
1980 - Loses to Thorburn 18-16 in his third World Championship final.
1981 - Beats Terry Griffiths to win second Masters title.
1982 - Wins his second world title by beating Reardon 18-15.
1983 - Wins the UK Championship by beating Steve Davis 16-15 in the Preston final.
1984 - Loses UK Championship final to Davis.
1986 - Head-butts UK Championship tournament director Paul Hatherell, he is fined £12,000 and banned from five tournaments.
1987 - Loses Masters final to Dennis Taylor
1990 - Threatens to have Taylor shot and then punches a tournament director at the World Championship, he is banned for the rest of the season.
1995 - Helps the European Pool team beat the USA in the Mosconi Cup.
1998 - October - Undergoes surgery to remove cancer from his throat.
2005-06 - Appears at the Irish Professional Championship but fails to get past the first round.
2010 - July 24 - Dies at the age of 61 after a long battle with cancer.