American Idol, in a special called "Idol Gives Back", will raise funds for charities in the U.S. and Africa.
During the 24 April episode, every vote cast via phone or text message, "Idol" sponsors Coca-Cola, AT&T and others will donate money to charity.
Organisations such as UNICEF, the Global Fund, Save the Children, Nothing but Nets and Malaria No More will benefit from the donations.
"Idol" creator Simon Fuller said he hoped the event would be a big success, "allowing us to continue to make these important, world-changing shows for many years to come."
"Idol Gives Back" also is providing a link on its website to One: The Campaign to Make Poverty History.
U2's Bono, co-founder of the One campaign, said "I wouldn't underestimate the reach of [Idol] or the impact its audience can have."
Gwen Stefani, Pink and Annie Lennox will also perform on the star-studded two-night American Idol charity.
Bono also is expected to sing, and Sacha Baron Cohen will appear in character as Borat. Other performers lined up include crooners Josh Groban and Michael Buble, and classical-crossover combo Il Divo.
"Idol Gives Back" is designed to raise awareness and funds for poverty-relief organisations that help children and young people in the U.S. and Africa. Fox has partnered on the project with Charity Projects Entertainment Fund.
