Former Formula One world champions Lewis Hamilton and Jenson Button have backed a fund to raise money for a teenage British Formula 4 driver who has had amputations to both of his legs.
Billy Monger, 17, was involved in a high-speed crash at Donington Park on Sunday.
Monger's JHR Developments team set up a JustGiving page on Wednesday afternoon with the aim of raising £260,000 and the target was reached within hours.
At time of writing well-wishers have donated more than £645,000.
Mercedes driver Hamilton, who has 4.32 million followers on Twitter, tweeted about Monger after hearing of the driver's injuries.
Hamilton tweeted: "I have only just seen the news of this tragic incident."
He later added: "Thoughts and prayers are with you and your family, @BillyMonger".
I have only just seen the news of this tragic incident. https://t.co/44xpCxvFKz— Lewis Hamilton (@LewisHamilton) April 19, 2017
Jenson Button made a £15,000 donation to Monger's Just Giving Page on Wednesday.
"Embrace the love from your family and friends during this tough time. Get well soon buddy. JB," Button wrote in a message accompanying the donation.
Button wrote on his Instagram account: "Hey guys this fellow racer Billy Monger had a big shunt this past weekend at Donington and sadly Billy has had amputations to both legs. This guy needs our help so if you can please donate, I will be doing as much as I can to help this dude out. The donations will be used to fund the care, treatments and therapies required by Billy in the immediate future and going forward, helping him to return to a full and active life. Info is on my bio."
JHR Developments made an announcement via their Twitter account to say that all donations would go "directly to Billy's future".
The tweet continued: "From all of us at JHR and the Monger family, we gratefully appreciate any donations no matter how big or small. Thanks for your support."
Monger, from Charlwood in Surrey, was left fighting for his life after he was injured in a collision with the Carlin car being driven by Finnish driver Patrik Pasma, which appeared to have stopped on the racetrack.
Onboard footage from a camera on Monger's JHR car showed him seeming to run into the back of Pasma's stationary car.
After being trapped in his car for an hour and a half at the Leicestershire circuit, the British driver was airlifted to the nearby Queen's Medical Centre in Nottingham.
A statement on the JustGiving page says: "After being involved in one of the most horrific crashes motorsport has seen Billy Monger is a teenager that needs little introduction. Thousands of people have already watched the haunting footage of the crash which left Billy fighting for his life.
"Sadly Billy has had amputations to both legs.
"Well known in motorsport for being not only an extremely talented young driver but for also being a truly special 17-year-old - loved and admired by his team, fellow competitors, supporters and of course his devoted family.
"Having always been a fighter Billy has already overcome big hurdles in his career - struggling for budget Billy has fought his way into top-flight motorsport, however, we now need your kindness and support to help give Billy and his family the best chance to fight these injuries that will affect Billy's life so massively."
The post, which is signed by the Monger family and Steven Hunter/JHR Developments, continues: "We are in the process of establishing a trust to receive, hold, manage and expend funds for Billy's benefit. In the meantime you can help start the process by donating online.
"Donations will be used to fund the care, treatments and therapies required by Billy in the immediate future and going forward, helping him to return to a full and active life."
- If you would like to contribute to Billy Monger's JustGiving page, details are here