The Prince and Princess of Wales made a large private gift that helped the London Air Ambulance charity raise £15 million.
While the specifics of William and Kate's contribution remain unknown, their assistance has been critical in meeting the aim.
The generous contribution will allow the organization to replace its old fleet of helicopters with two cutting-edge Airbus H135s.
This comes as the royal family is scheduled to get two taxpayer-funded helicopters.
William, a supporter of the London Air Ambulance, has actively participated in the campaign, attending fundraising galas, including one with Tom Cruise.
He has also organized critical meetings with charity officials and potential contributors, which has boosted the appeal's success.
Jonathan Jenkins, CEO of London's Air Ambulance Charity, thanked the Prince of Wales for his essential support.
"The support of the Prince of Wales throughout our campaign has been invaluable, both publicly and privately," Jenkins told the press.
He emphasized the significance of his engagement, stating that the Prince's addresses at two major fundraising galas collected more than £2 million and considerably increased the campaign's visibility.
"Without his support — along with countless corporate sponsors, private backers, and community fundraisers — this appeal simply would not have been possible," according to Jenkins.
The organization was able to replace its obsolete fleet with two new Airbus H135 helicopters thanks to generous contributions from all throughout the city.