Lewis Hamilton has pledged $500 000 to "support the animals, wildlife volunteers and rural fire services" affected by the bushfire crisis in Australia.
The six-time Formula One world champion announced the donation on Twitter on Thursday, saying: "It breaks my heart to see the devastation the Australian bushfires are causing to people and animals across the country.
"I'm pledging $500k to support the animals, wildlife volunteers and rural fire services. If you are able to, and you haven't already then you can donate too."
The catastrophic bushfires have killed at least 26 people, destroyed more than 2000 homes and scorched some (80 000 square kilometres).
The 35-year-old Briton's message was accompanied by a video of a koala bear being rescued from flames.
University of Sydney scientists estimate one billion animals have lost their lives in the fires. The figure includes mammals, birds and reptiles, but not frogs, insects or invertebrates.
In a separate post on Instagram Hamilton wrote: "It saddens me deeply to know that over 1 billion animals in Australia died a painful death, no way out, not their fault."
"My love of animals is no secret and I can't help but grieve for the defenceless animals thought to have died so far, pushing certain species closer to extinction."
He urged Australia to "keep fighting".
"I'm lucky enough to visit Australia often and I know first-hand how beautiful the country is."
He said he had spoken to people "who are working at the heart of this and I'm filled with admiration for everything they are doing".
And he concluded his heartfelt message by imploring his 14-million Instagram followers and fans "to join me in thinking about the impact we are having on our planet".
"Let's work together to make small changes, and encourage our family and friends to do the same, so we can help shift the direction we're going in."
Australian tennis players Nick Kyrgios and Ashleigh Barty and Australia's cricketers are among many others to have pledged support to the crisis enveloping their country.