Kanye West is now part of the lineup for Saturday's Live 8 concert in Philadelphia.
Organizers say Rita and Stephen Marley will also perform. They join musicians that include Alicia Keys, Will Smith, Destiny's Child and Stevie Wonder.
The event is part of a series of concerts planned around the world to raise awareness of poverty in Africa.
Nine other cities will host concerts: London, Paris, Rome, Berlin, Moscow, Johannesburg, Tokyo and Toronto, with a related all-African concert at the Eden Project in southwest England.
More than a million people may attend, and organizers say 85 percent of the world's population will have access to a television, radio or Internet broadcast of the day's events.