Bono and Youssou N'Dour for Africa
Bono and Youssou N'Dour are among leading activists who on Thursday will call on world leaders to avert "a great 21st-century tragedy" unfolding in the horn of Africa.
Urgent action against famine is urged by 56 African artists and opinion-formers, backed by international campaigners, in a joint letter to this week's UN summit in New York.
They warn that food shortages in east Africa have already killed tens of thousands of children and that millions of more people are threatened. The UN estimates that $2.5bn (£1.6bn) is needed for the humanitarian response, particularly to tackle famine in Somalia, but there is a current shortfall of around $920m (£590m).
The group also urges African and other world leaders to keep their promises to invest in long-term agriculture projects to improve food security so that famines can be prevented in future.