Since Bob Geldoff brought a group of musicians together for the famine-relief Live Aid concerts 25 years ago, celebrities have come to play a high profile role in aid and development.

Celebrities are leading campaigns, championing causes and meeting world leaders on behalf of the poor. But is this a good thing? Do celebrities cause more harm than good? Or are they a necessary evil?

Madeleine Bunting is joined by the executive director of the advocacy organisation ONE, Jamie Drummond, assistant head of the Africa Programme at Chatham House, Tom Cargill, and professor of economics at New York University and co-director of its development institute, William Easterly, to debate the issue.

We also hear the views of the director of the global justice organisation, the World Development Movement, Deborah Doane, the founder of the Bianca Jagger Human Rights Foundation and the Council of Europe's goodwill ambassador, Bianca Jagger, and the professor of political science at the University of Waterloo, in Canada, and author of the book Celebrity Diplomacy, Andrew Cooper.

- Research by Claire Provost