Two-time NASCAR Cup Series champion Kyle Busch died from an undisclosed illness on Thursday at the age of 41.The news was sudden given that Busch’s family announced earlier in the day that he was hospitalized. The “severe” illness that his family said he suffered remains unspecified.Busch was previously prepared to compete in the Coca-Cola 600 at Charlotte Motor Speedway on Sunday.

“We are saddened and heartbroken to share the news of the passing of Kyle Busch, a two-time Cup champion and one of our sport’s greatest and fiercest drivers,” NASCAR said in a statement. “We extend our deepest condolences to the Busch family, Richard Childress Racing and the entire motorsports community.”

Before his death, Busch was driving the No. 8 Chevrolet Camaro ZL1 for the Richard Childress Racing team.

Speedway Motorsports President Marcus Smith also released a statement in honor of Busch’s storied career and life.

“Kyle Busch was a champion among champions — a once-in-a-generation competitor whose grit, unmistakable driving style and relentless pursuit of excellence elevated him to a place among the very best drivers in our sport,” Smith said in part. “When Kyle climbed behind the wheel, he brought an intensity and determination that demanded respect from his competitors and inspired fans throughout motorsports.”