Lewis Hamilton says he will donate more than £380,000 to support the fire service and animal welfare charities affected by fires in Australia.
The Formula 1 world champion pledged US $500,000 and says he "can't help but grieve for the defenceless animals thought to have died" in the fires.
The bushfires have burnt more than 6.3 million hectares across the country and 27 people have died.
Hamilton urged Australia to "keep fighting" in a message on Instagram.
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Alongside a video of a koala being rescued, the 35-year-old Mercedes driver 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.
"I'm lucky enough to visit Australia often and I know first-hand how beautiful the country is. Keep fighting Australia. I've spent some time speaking to people in Australia who are working at the heart of this and I'm filled with admiration for everything they are doing.
"I implore you 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."
Hamilton's donation - which is in US dollars and converts to roughly £383,000 - will go to WIRES Wildlife Rescue, WWF Australia and the Rural Fire Service.
The state of New South Wales has seen more than 1,300 houses destroyed and around five million hectares impacted by the fires.
On Thursday, the state of Victoria declared a state of disaster. Despite a national bushfire crisis raging since September, the south-eastern state is only now entering what is considered to be its worst fire months.
Renault's Australian driver Daniel Ricciardo has used social media to urge people to donate and said his country was "suffering".
Australian tennis players Nick Kyrgios and Ashleigh Barty are among many other sports stars, including Australia's cricketers, who have also pledged money.