The owner of Leicester City FC died when his helicopter crashed outside the stadium, the club has confirmed.
Billionaire Vichai Srivaddhanaprabha, two members of his staff, the pilot and a passenger were killed when the aircraft spiralled out of control and crashed in a fireball on Saturday, reports BBC.
It had just cleared the King Power Stadium when it came down at 20:30 BST.
The Duke of Cambridge said he was lucky to have known Mr Vichai, describing him as a dedicated family man.
Leicestershire Police said it believed the other people killed in the crash to be two members of Mr Vichai's staff - Nursara Suknamai and Kaveporn Punpare - pilot Eric Swaffer and his partner Izabela Roza Lechowicz.
Mr Swaffer had over 20 years' flying experience as a private jet and helicopter pilot.
His career included flying helicopters for live media broadcasting including Channel 4's The Big Breakfast and the Virgin Radio traffic helicopter.
Mr Swaffer's friend Lucie Morris-Marr said he was a "veteran in the field" and would have done all he could to prevent lives being lost in the crash.
She described him as a "funny and vivacious" man who was in an "aviation love story" with Ms Lechowicz.
"Not many people get to work and travel with their soulmate, travelling the world going to glamorous places," she said.
The couple were professional pilots who lived together in Camberley, Surrey. Ms Lechowicz moved to the UK from Poland in 1997.
In a statement, the Polish embassy said: "With great sadness, we received the news about the death of Izabela Lechowicz in the Leicester catastrophe.
"She was a great pilot, winner of the #Polka100 contest. It contributed to the creation of a positive image of Poland in the UK."
Mr Vichai, 60, who was married and had four children, bought Leicester City for £39m in 2010.
Under his ownership the Foxes won the Premier League in 2016, having started the season as 5,000/1 outsiders.
In a statement, Leicester City said the club's thoughts were with "the Srivaddhanaprabha family and the families of all those on-board at this time of unspeakable loss".
Prince William, who is president of the FA, said Mr Vichai made a big contribution to football, adding that Leicester City's Premier League title-winning season "captured the imagination of the world".
"He will be missed by all fans of the sport and everyone lucky enough to have known him," he said.
Former England and Leicester striker Gary Lineker tweeted to say he was "deeply saddened" to hear of Mr Vichai's death.
Speaking outside the stadium, club ambassador Alan Birchenall said Leicester City owed "everything" to Mr Vichai.
"We wouldn't have won it [the Premier League] without him," he said. "We wouldn't have got near it without him.
"There won't be a dry eye among any of the staff today."
Thousands of supporters have shared an amended image of the club's emblem with a crying fox on it on social media as a mark of respect.
British Prime Minister Theresa May said: "The outpouring of grief is a testament to how many people's lives were touched by those on board."
The club described Mr Vichai as "a man of kindness, of generosity and a man whose life was defined by the love he devoted to his family and those he so successfully led".
"Leicester City was a family under his leadership. It is as a family that we will grieve his passing and maintain the pursuit of a vision for the club that is now his legacy," it added.
A book of condolence will open at the King Power Stadium at 08:00 GMT on Tuesday, with an online version on its website for those unable to visit in person.
The team's next fixture against Southampton in the EFL Cup, scheduled for Tuesday evening, has been postponed. The players will also wear black armbands this week against Cardiff in the Premier League.
Mr Vichai's two horses, due to run at Leicester Racecourse on Monday, have been withdrawn. Jockeys there will wear black armbands at the meeting as a mark of respect.
Leicester goalkeeper Kasper Schmeichel, who witnesses said ran out of the stadium towards the crash scene, said Mr Vichai had "changed football forever".
"I cannot believe this is happening. I am so totally devastated and heartbroken," he added.
Club captain Wes Morgan tweeted: "Absolutely heartbroken and devastated regarding the news of our chairman. A man that was loved and adored by everyone here at lcfc."
Premier League chief executive Richard Scudamore said: "Vichai was a gentleman who graced the game with his civility and charm and we will miss him enormously.
"His impact on Leicester - the football club and the city - will be remembered forever."
Kasabian band member and Foxes fan Serge Pizzorno called Mr Vichai "an unbelievable human being".
"It never felt like he acquired this club to then sell on after a few years," he said. "He bought into everything, bought into the city, supported everything around it.
"He made all our dreams come true."
Paris Saint-Germain, Inter Milan, West Ham United, Tottenham Hotspur, Nottingham Forest and Swansea City were among the football clubs that passed on condolences to Leicester.
The helicopter came down in a car park near the stadium just over an hour after Leicester had drawn 1-1 against West Ham United in the Premier League.
Leicestershire Police confirmed no-one else had been injured and said the Air Accidents Investigation Branch (AAIB) is leading the investigation.