Bono has launched a new mobile phone designed to help tackle Aids in Africa.
"You don't have to change your number," the U2 lead singer and today's editor of The Independent, said. "But you can change the world - for someone whose world is worth changing."
The RED phone is expected to raise tens of millions of pounds for Aids drugs and education, as a result of an "unprecedented" collaboration between rival operators in Britain's telecoms industry.
Whatever network they are on, customers can switch to the ultra-thin red handset - equipped with an MP3 player - and raise funds to fight Aids. The Global Fund for Aids projects will receive £10 from the sale of the Motorola handset and a further 5 per cent of call revenues.
To use the new phones, priced at £149, customers need only transfer the sim card from their existing phone: the network company will do the rest.
The RED phone is the latest step in the campaign by Bono and Bobby Shriver, the American philanthropist and member of the Kennedy family, to enlist global business in the fight against Aids.
At the Davos summit of world leaders in March, Bono and Mr Shriver announced that four finance and fashion brands had created RED products.
American Express launched a RED credit card, Converse designed two sports shoe lines, Gap a T-shirt with plans for 50 lines of clothing by October, and Armani produced sunglasses to be followed by a range of RED clothing later this year.
The money raised will finance Aids work aimed at women and children by the Global Fund, which also fights TB and malaria.
The sale of three handsets provides one year's worth of school materials and daily hot meals for a child orphaned by Aids. Five per cent of the annual phone bill can provide 180 treatments to prevent the transmission of Aids from a mother to a child.
Bono, Mr Shriver and telecoms chiefs - representing Motorola, Carphone Warehouse, O2, Orange, Vodafone, T-Mobile, Tesco, Virgin Mobile and Fresh - launched the handset at a restaurant well known to the music industry, No 5 Cavendish Square.
Bono told journalists: "This is a historic moment, not just in marketing but in the battle against this tiny virus about which there will be a very large chapter written in the history of these times."
He credited Charles Dunstone, the chief executive of Carphone Warehouse, with having the idea of recruiting all the telecoms companies to combat what he called "the greatest health crisis in 600 years".
He explained: "Charles had this idea that he thought might be more marketable ... to get the various networks to work together."
He went on: "I thought that was like getting Felipe Scolari, Guus Hiddink, and Jurgen Klinsmann - and throw in another few World Cup managers - to work with [England's new manager] Steve McClaren. I thought it was just the maddest idea."
Rather than targeting the philanthropy of multinational companies - who had contributed only $2m (£1.1m) to the Global Fund - the whole idea behind RED was to put a commercial proposition to big business that worked for the companies and for developing countries, the U2 singer said. He added: "We had the student campuses and the church halls but we didn't have the high street."
But he stressed that RED products had to be fashionable and appealing - "sexy" products marketed with the panache of a brand such as Nike.
Of his ambition for the RED phone, the singer said: "I would be very disappointed if the telephony piece did not raise hundreds of millions of dollars for the Global Fund.
"One of the reasons we are picking on the Aids emergency is that all the work we are doing, from Live Aid and Make Poverty History, is being undone by this tiny virus."
Mr Dunstone said: "The thing that strikes you is that the mobile phone has become such a part of people's lives. It says something about their personality and typically people only have one so if you can find a way to link these terrible circumstances in Africa with this product it could be a really powerful combination."
Promoting the RED phone, he said: "You don't have to change your network, you don't have to sign anything, you can use your other sim card, put it in this and from then on, 5 per cent of everything you are spending goes to fighting Aids in Africa."