"Our entire NASCAR family is heartbroken by the loss of Kyle Busch," the association said in a joint statement with the Busch family on X. "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."

"NASCAR lost a giant of the sport today, far too soon," the statement added. "During this incredibly difficult time, we ask everyone to respect the family's privacy and continue to keep them in your thoughts and prayers."

More details have since come to light, including that Busch passed out while testing the Chevrolet racing simulator a day before his death, as several people familiar with the situation told the Associated Press.

The athlete—who is one of the most decorated drivers in the sport's history—had become unresponsive before being transported to a nearby hospital, the outlet reported.

But Busch had been struggling with his health earlier in the month, too, requesting that a doctor attend to him after his race at Watkins Glen International May 10.

"Can somebody try to find Bill Heisel? He's the kindred doctor guy," he asked into a radio transmission shared on X by FOX: NASCAR. "Tell him I need him after the race, please."

He added that he was "gonna need a shot," though the nature of the injection was not disclosed.

As for Busch's legacy, his peer Ricky Stenhouse Jr. shared that his time on the racetrack will never be forgotten.

"I've raced against Kyle for a long time, and anyone who's lined up next to him knows exactly what made him special," he wrote on X. "He gave you everything he had, every single lap, and he made all of us better for it."

While Busch's family and peers continue to mourn the legendary driver, keep reading for a look at his life on and off the track.