Capital FM's charity, Help a London Child, is asking the public for cash donations as part of this year's Christmas appeal for the first time in its 28-year history.
The annual appeal provides around £1m worth of toys and food to London's most disadvantaged children.
Almost £150,000 of this will be supplied by Walt Disney's charitable arm, DisneyHand, and other companies will donate as well.
The 'Give an Hour' online appeal, at capitalfm.com/halc, asks people to pledge one hour of their salary to the charity, so it can buy the children presents.
The move represents a shift in focus away from inviting donors to buy film premiere tickets or auctioned items, as it has done in previous appeals.
Verity Rowles, the charity's fundraising manager, has set a conservative fundraising target of £15,000, because she said that regular listeners would be unfamiliar with the concept in relation to Help a London Child.
"We are not expecting a huge response because it will take time for it to sink in," said Rowles. "And our sole marketing is through radio, where messages need to be aired four times to register. But hopefully people will get used to the idea and we will raise more next time."
By asking for money rather than second-hand toys from the public, the charity wants to improve its bulk-buying power so it can give the children better quality goods.
DisneyHand will contribute soft toys, books and videos from the Disney Store, Buena Vista Home Entertainment and Disney Publishing, donate proceeds from 300 UK film premiere tickets of Freaky Friday, and provide 100 volunteers to help package toys at the Capital Radio Warehouse.
Claire McSharry, corporate communications manager at The Walt Disney Company, said: "The tie-in fits into the overall appeal of our outreach programme of making the dreams of children come true."