The gold medal winning diver’s father Robert died aged 40 from a brain tumour in 2011.
The Brain Tumour Charity has launched an appeal to help raise £450,000 needed to fund the new three-year trial, which is due to begin recruiting some 232 patients at 15 hospitals across the UK early next year.
In a video to promote the trial, Daley said: “We are reaching out to all you individual heroes and supporters, to help fund this groundbreaking trial.
“When you donate, you’ll receive a link for your social media badge of honour. Join our community, spread the word and help us pave the way to beating brain tumours.”