NASCAR legend Jimmie Johnson couldn't find the words to describe the shocking and sudden death of his former teammate and fellow champion Kyle Busch.

"I'm kinda lost for words at this moment, but we're gonna miss you buddy. Gone too soon to say the least," Johnson told "CBS Mornings" on Friday.

Busch's family posted on his social media Thursday morning he had been hospitalized with a severe illness and would not be competing at this weekend's race in Charlotte. Just a few hours later, NASCAR announced Busch had died.

"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 wrote on social media.

Busch was beloved by many fans for his take-no-prisoners driving style, an attitude that earned him the nickname "Rowdy."

"[I'll remember] just that spirited, ruthless competitor on track. And I use ruthless in the best way possible. If you took an inch, he was going to take two," Johnson told "CBS Mornings" on Friday. "And there was an amount of respect on the track that you just showed him, as a result. At the same time, [he] would race you so hard and so clean, and just an incredible competitor."

Busch won Cup Series titles, the sport's highest level, in 2015 and 2019. Busch is the all-time leader in wins in the O'Reilly Auto Parts Series (102) and Craftsman Truck Series (69), considered the second and third tier in the sport respectively. Combined with 63 wins in the Cup Series, he holds the most wins ever by a driver in NASCAR's three top divisions (234).

Johnson, who has a record-tying seven Cup Series titles, was teammates with Busch at Hendrick Motorsports early in Busch's career. From 2004 to 2007, Johnson got to know the young Busch — just 18 years old at the time of his Cup Series debut — not just as a teammate but as a person and a close friend.

"Fierce competitor, but at the same time, helmet comes off with his family, just, you know, a dad, a husband and somebody that cared deeply about his children and heavily involved," Johnson said. "So, you know, the guy off the track is somebody I'll certainly remember most, and just feel for his family and young children growing up with this void."

"Experiencing some tragedy on my own, and understanding the implications, we still try to continue on," he added. "My heart breaks for him."

Busch leaves behind his wife, Samantha, and two young children, Brexton, 11, and Lennix, 4. 

An exact cause of death has not been released.