The IT industry's annual Byte Night is aiming to raise £500,000 this year to help homeless youngsters.
Byte Night, which is celebrating its tenth anniversary, will see 500 top business and IT executives from leading companies, including BT, Barclays, Royal Bank of Scotland, Dell and Fujitsu, sleep out in a number of locations across the country, including Birmingham, Edinburgh, Manchester and Thames Valley.
They will be joined by actresses Jenny Agutter and Lindsey Coulson who will spend the night under the stars in central London.
Jeremy Paxman, Angus Deayton, Ian Hislop, Nick Ross, Alexei Sayle, Mike Read and Boris Johnson have joined forces with figures from the IT industry to back the campaign, by contributing messages of support for the 3 October sleep out event.
Arsenal football players, along with Ricky Hatton, Steve Davis, and Ainsley Harriott have also thrown their weight behind the event by contributing items for a silent auction.
Co-founder of Byte Night Ken Deeks said, "I am thrilled that so many celebrities have given their time to support Byte Night. My thanks goes out to them and everyone else involved this year.
"The scale of youth homelessness in this country is an area of huge concern. The pressing problem is not going to go away, especially with the onset of the economic slowdown. However, there is a burning passion among IT representatives to do more personally, and they want to see that compassion reflected by the companies they work for."