Mr Brown has said he is a fan of TV talent shows
Gordon Brown has appeared on the US talent show American Idol to promise to buy 20 million mosquito nets for malaria-hit countries.
In a pre-recorded video for a charity special he said there was "nothing more amazing than saving a life".
The PM signed off with the blessing: "Thank you and God bless you all."
Mr Brown invited American Idol judge Simon Cowell - who also appears on Britain's Got Talent and X-Factor - to Downing Street last December.
'We admire US'
The US show has attracted more than 30 million viewers on several occasions and counts Grammy award-winner Kelly Clarkson among its previous contestants.
In his address to US viewers, Mr Brown, who is an avowed fan of talent shows, said: "All year on Idol, it's the talent of the American people we admire. But tonight, it's your generosity."
He added that with 120 million more mosquito nets, costing $10 (£5) each, "all families could sleep safe at night".
Mr Brown also said he would be "urging other world leaders to play their part".
Malaria kills an estimated 3,000 children a day, most of them in Africa.
Peter Chernin, chairman of Malaria No More, said: "I applaud the United Kingdom's commitment to provide bed nets to Africans at risk of malaria and salute Gordon Brown's bold leadership in the fight against this treatable and preventable disease."