U2 lead singer and humanitarian Bono speaks at the Economic Club of Grand Rapids at the DeVos Place Convention Center in Grand Rapids, Michigan May 4, 2006.[Reuters]

Irish rock star and anti-poverty campaigner Bono is taking part in this week's "American Idol" charity fund-raiser, organizers said on Tuesday.

The U2 lead singer will appear in a prerecorded segment on Wednesday night urging viewers of the show to call in donations to charities that work with young people in Africa and the United States.

Bono spent last weekend with the remaining six "Idol" contestants, who will perform "American Prayer" -- the song he wrote some years ago with Dave Stewart about the AIDS emergency in Africa -- during Wednesday's two-hour special "Idol Gives Back."

Comedian Ellen DeGeneres will host the show from the Disney Hall in Los Angeles where stars including Celine Dion, Kelly Clarkson and Gwen Stefani will perform and dozens more stars are expected to appear on video. Bono will not be performing live himself.

Bono is a leading spokesman for the ONE Campaign to Make Poverty History -- a coalition of nonprofit and faith-based groups that encourages Americans to fight AIDS and extreme poverty in Africa.

The first fund-raising venture by the hit TV show is expected to raise millions of dollars for Save the Children, UNICEF, Malaria No More, The Global Fund and Nothing But Nets for youth relief programs in Africa and poverty-hit areas of the United States including hurricane ravaged Louisiana.