Jenson Button has pledged £15,000 to a fund-raising page set up to support a British Formula 4 driver who had both legs amputated following a crash.
Billy Monger, 17, drove at high speed into the back of a car which seemed to have stopped on the track during Sunday’s race at Donington Park.
Lewis Hamilton has also offered support, tweeting: “Thoughts and prayers are with you and your family.”
More than £390,000 had been raised by 10:00 BST on Thursday.
Monger, who has been described as “an extremely talented young driver” had to be extracted from his vehicle at the Leicestershire track and airlifted to hospital.
Button, the 2009 world champion who retired last year but will make a one-off outing for McLaren at next month’s Monaco Grand Prix, was among the first to voice his support for Monger.
“This guy needs our help. I will be doing as much as I can to help this dude out,” he wrote on Instagram.
British ex-F1 driver Max Chilton also appeared to make a pledge on the page. Donations also appeared to be made by former F1 drivers Karl Wendlinger and Andre Lotterer, as well as touring car driver Jason Plato and American Nascar racer AJ Allmendinger.
Williams’ Brazilian driver Felipe Massa showed his support on Twitter, writing: “Let’s help him. I’ll do my best.”
Ex-F1 driver Mark Webber wrote “keep boxing mate”, while the Mercedes, Force India and McLaren teams have also showed their support on social media.