Bono has shared the stage with a local band while in the West African state of Mali.
Reuters reports that the singer visited the Piroge bar and restaurant in the capital Bamako on 22 May where the Samaquera band were playing; the group plays songs that are more than 1,000 years old.
Bono listened to the band's set and joined them for their last song, singing an African chant with the group for about 10 minutes.
Commenting afterwards, Bono said: "It's astonishing music. I wonder if the songs are exactly as they were back then or if they've been changed."
Bono's six-country tour of Africa is to show the progress in treating people with HIV-AIDS and highlight the need for trade growth and the campaign to cancel African debt.
