The former rugby league player has called on UFC fighter Soa "The Hulk" Palelei to join him for this year's challenge to raise money for Telethon.
"We can keep each other company and motivate each other," Mr Fuller said.
"The last 12 hours to reach 24 is very mentally hard."
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READ NOWPalelei said 24 hours was nothing compared to what sick children went through at Princess Margaret Hospital (PMH).
The father of three is no stranger to PMH; his youngest son Jonah (9) was diagnosed with epilepsy last year.
However, he said spending 24 hours on the ergo grinder would be very different to his usual strength and conditioning and sparring training sessions.
This will be the sixth 24-hour challenge for Fuller, who has two children.
"We raised $60,000 last year so we hope to break $100,000 this year," he said.
Sponsor Peard Real Estate has got the fundraising tally started with a $40,000 donation.
Donate at https://mattandsoa24hrgrind.everydayhero.|com/au/telethon or visit the duo at Telethon from October 17 to 18.