Kyle Busch, a two-time NASCAR Cup Series champion, has died at the age of 41, NASCAR announced Thursday.

“We are saddened and heartbroken to share the news of the passing of Kyle Busch,” NASCAR shared on X, remembering him as “one of our sport’s greatest and fiercest drivers.”

“We extend our deepest condolences to the Busch family, Richard Childress Racing and the entire motorsports community,” NASCAR said.

Busch had been hospitalized with a severe illness, his family said earlier on Thursday, and was undergoing treatment.

They did not disclose what the illness was.

“Our entire NASCAR family is heartbroken by the loss of Kyle Busch,” the Busch family, Richard Childress Racing and NASCAR said in a joint statement. “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.”

“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 statement continued. “NASCAR lost a giant of the sport today, far too soon.”

The news comes 11 days after Busch radioed into 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 ranked 24th in the Cup Series standings, with two top-10 finishes in 12 races this season. A Las Vegas native, Busch won championships in 2015 and 2019.

His family said earlier Thursday that the illness would cause him to miss competing at Charlotte Motor Speedway this weekend. It would have been the first time in over a decade that he would have missed a Cup Series race.

In 2015, he missed the first 11 races of the season while recovering from a compound leg fracture and broken foot following a crash during the Xfinity Series season opener at Daytona International Speedway.

Speedway Motorsports, which owns and operates Charlotte Motor Speedway, where Busch was set to compete Sunday in the at the Coca-Cola 600, paid tribute to driver, hailing him as a “once-in-a-generation competitor.”

“At Charlotte Motor Speedway, Kyle etched his name in history, earning more victories across NASCAR’s top three series than any other driver in our sport, highlighted by his victory in the 2018 Coca-Cola 600,” CEO Marcus Smith said.

Smith remembered Kyle as a “devoted father and a loyal friend” who “proudly shared the track with his son, Brexton.”

Known as “Rowdy” and “Wild Thing” for his post-race fights, regular feuds with other drivers and sometimes outlandish behavior, the multi-talented and polarizing Busch stormed on the Cup Series scene in 2005 by winning Rookie of the Year.

Busch won 234 races across the sport’s three national series, more than any driver in history. He had 63 Cup victories along with 102 O’Reilly Auto Parts wins and 69 Trucks victories — both records.

He was in his fourth season at Richard Childress Racing after winning titles with Joe Gibbs Racing. His last win came in 2023, his first with RCR.

Busch had struggled to find consistency since leaving for RCR. That lack of success led to a recent spat with former Joe Gibbs Racing teammate Denny Hamlin, who appeared to criticize Busch’s odds of going “back to Victory Lane on a regular basis.”

The two appeared to have made amends, with Hamlin later saying Busch is on the “Mount Rushmore” of racing.

Hamlin offered his condolences Thursday following the news of Busch’s passing.

“Absolutely cannot comprehend this news. We just need to think of his family during this time. We love you KB,” Hamlin wrote on X.

NASCAR driver and team owner Brad Keselowski wrote on X, “Absolute shock. Very hard to process. Hug your loved ones.”

“Rest easy, Rowdy. The sport won’t be the same without you,” driver Ricky Stenhouse Jr wrote.

After earning his 69th career Trucks Series race win at Dover last weekend, Busch was asked how many races he wanted to win before he stops racing.

“You take whatever you can get, man,” Busch said. “You never know when the last one is going to be, so cherish them all — trust me.”

Busch is survived by his parents, his wife Samantha, son Brexton, 11, and daughter Lennix, 4.