The fund, set up by Melanie and Carl Hodgkiss to pay for alternative treatment for their four-year-old daughter Aria who has brain cancer, aimed to raise £60,000.
The donations from the Hollywood stars and owners of Wrexham Football Club pushed the fund over its target.
As seen on Aria's GoFundMe, the two top donations are from Reynolds and McElhenny who put £10,000 each towards the fund.
Aria's mother Melanie commented: "This is mind-blowing. I was in tears, happy tears. Then I saw a tweet from Rob saying 'Aria you look beautiful!' I couldn't believe he had donated - it's amazing."
She added: "Then I was sat at the kitchen table and there was another donation of 10k from Ryan. I said to Aria - you are famous and she was saying, 'I'm famous!' I am in total shock."
Melanie also thanked the duo on Twitter for their donations.
— Aria VS Dipg (@AriaVsDipg) August 10, 2022
Last year, Aria was diagnosed with Diffuse Intrinsic Pontine Glioma, a rare terminal type of brain cancer that cannot be operated on.
An experimental drug called ONC201 is available to combat the disease but not through the NHS. The treatment is available in Germany and can cost around £3000 per month.
Reynolds and McElhenney bought Wrexham Football Club in 2020 with the duo being seen regularly at games once Covid-19 travel restrictions allowed.
Their ownerships of the non-league football team is set to be depicted in the Disney+ documentary series Welcome to Wrexham which premieres later this August.
A synopsis for the series reads: "From Hollywood to Wales, from the pitch to the locker room, the front office to the pub, Welcome to Wrexham will track Rob and Ryan’s crash course in football club ownership and the inextricably connected fates of a team and a town counting on two actors to bring some serious hope and change to a community that could use it"
Watch below: Ryan Reynolds and Rob McElhenney bought soccer team without ever meeting each other