Kyle Busch, a two-time Cup Series champion who won more races than anyone across NASCAR's three national series, has died at 41.
The Busch Family, Richard Childress Racing and NASCAR issued a joint statement on Thursday saying Busch had died after being hospitalised. No cause of death was given.
Busch's family said earlier he had been hospitalised with a "severe illness," three days before he was to compete at the Coca-Cola 600 at Charlotte Motor Speedway.
"Our entire NASCAR family is heartbroken by the loss of Kyle Busch," the statement said.
"A future Hall of Famer, Kyle was a rare talent, one who comes along once in a generation. He was fierce, he was passionate, he was immensely skilled and he cared deeply about the sport and fans."
The statement went on to say "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.
"His sharp wit and competitive spirit sparked a deep emotional connection with race fans of every age, creating the proud and loyal 'Rowdy Nation.'"
The news comes 11 days after Busch radioed his crew near the end of a Cup Series race at Watkins Glen asking a doctor to give him a "shot" after he finished the race.
According to the TV broadcast, Busch had been struggling with a sinus cold that was exacerbated by the intense G-forces and elevation changes at the New York road course.
Busch finished the race in eighth place.
Busch competed at Dover last weekend and won the Trucks Series race for Richard Childress Racing. He finished 17th at the NASCAR All-Star race.
"Absolute shock. Very hard to process," veteran NASCAR driver Brad Keselowski posted on social media.
NASCAR driver and former teammate Denny Hamlin posted on social media: "Absolutely cannot comprehend this news. We just need to think of his family during this time. We love you KB."
A polarising figure known as "Rowdy" and "Wild Thing" for his post-race fights, regular feuds with other drivers and sometimes outlandish behaviour, the multi-talented Busch stormed on the Cup Series scene in 2005 by winning Rookie of the Year.
He went on to win championships in 2015 and 2019 for Joe Gibbs Racing.
From Las Vegas, Busch experienced unrivalled success across NASCAR's three national series winning a combined 234 Cup, O'Reilly Auto Parts and Trucks Series races. He had 63 Cup victories along with 102 O'Reilly Auto Parts wins and 69 Trucks victories - both records.
Kyle Busch was said to be ready to race at NASCAR's top level at 16, but a cigarette settlement banned his debut and he had to wait until he was 18. At the time Kurt Busch said "if you think I'm good, wait until you see my brother."
Busch is survived by his wife Samantha and children Brexton and Lennix.
