British Formula One world champions Jenson Button and Lewis Hamilton have paid tribute to fellow Brit Dan Wheldon, the IndyCar driver killed in a 15-car crash during an Indy 300 race in Las Vegas.
Wheldon, 33, was airlifted to hospital after he was involved in the horrific crash in lap 11 of the race on Sunday but died of his injuries.
Button, the 2009 Formula One world champion, posted his condolences on Twitter.
"Just woken up to the most horrific news... Dan Wheldon RIP.
"I have so many good memories of racing with Dan in the early 90's, a true fighter. We've lost a legend in our sport but also a great guy.
"I can't begin to imagine what his family are going through and my thoughts are with them at this very difficult time."
Hamilton, Button's Mercedes McLaren teammate, also spoke fondly of Wheldon, who leaves behind a wife and two young children.
"This is an extremely sad day.
"He was an extremely talented driver. As a British guy, who not only went over to the States but who twice won the Indy 500, he was an inspirational guy, and someone that every racing driver looked up to with respect and admiration."
Wheldon moved to the United States in 1999 and six years later became the first Englishman since Graham Hill in 1966 to win the Indianapolis 500.