Nascar champion Kyle Busch dies aged 41

Two-time Nascar Cup Series champion Kyle Busch has died, aged 41.

The sudden passing of the Nascar legend, who was ninth on the circuit's all-time win list, was announced in a joint statement on Thursday by the Busch family, Richard Childress Racing and Nascar.

They did not share a cause of death. Busch's representatives had said earlier on Thursday that he had been sent to hospital with a severe illness.

"A future Hall of Famer, Kyle was a rare talent, one who comes along once in a generation," the statement reads. "He was fierce, he was passionate, he was immensely skilled and he cared deeply about the sport and fans. ... Nascar lost a giant of the sport today, far too soon."

At the time of his death, Busch was in his 22nd full-time season in Nascar's top division, where he had won two Cup Series titles and 63 races.

"Throughout a career that spanned more than two decades, Kyle set records in national series wins, won championships at Nascar's highest level and fostered the next generation of drivers as an owner in the Truck Series," the statement said.

"His sharp wit and competitive spirit sparked a deep emotional connection with race fans of every age, creating the proud and loyal 'Rowdy Nation.'"

Busch was scheduled to compete at the Coca-Cola 600 at Charlotte Motor Speedway over the upcoming holiday weekend in the United States.

Earlier on Thursday, Busch's family said in a statement that he was in hospital due to a severe illness.

He was undergoing treatment, they said, and would not compete in any of his scheduled activities over the coming weekend.

The announcement of his death came hours later.

Busch is survived by his parents, his wife, and two young children.

Tributes poured in following the announcement of Busch's sudden death.

"Absolutely cannot comprehend this news," former teammate Denny Hamlin wrote on social media. "We just need to think of his family during this time. We love you KB."

Nascar driver Brad Keselowski said on social media: "Absolute shock. Very hard to process."

Speedway Motorsports, which owns Charlotte Motor Speedway where Busch was set to compete this weekend, remembered him as a "champion among champions" and as a "once-in-a-generation competitor".

Dale Earnhardt Jr, who clashed with Busch early in their respective careers, said in a statement: "We luckily took the time to figure out our differences and that was something he instigated with a conversation in his bus around how we each managed our racing teams. ... But it was he who made the effort for that to be possible."

He continued: "My heart is broken for the Busch family. I will never be able to make sense of this loss but I am thankful that we had found a way to become friends."