The additions were announced Thursday, one day after organizers announced that rapper 50 Cent would no longer be able to perform at the free show.
The lineup also includes host Will Smith and Bon Jovi, the Dave Matthews Band, Jay-Z, Kaiser Chiefs, Keith Urban, Maroon 5, P. Diddy, Rob Thomas, Sarah McLachlan and Stevie Wonder.
The Philadelphia show is one of five concerts aimed at raising awareness of poverty in developing countries, all taking place July 2, days before G-8 leaders meet in Scotland; the other concert sites are London, Paris, Berlin and Rome.
Destiny's Child will launch the North American leg of the "Destiny Fulfilled ... And Lovin' It" tour in St. Louis on July 9. At a recent concert in Barcelona, Spain, the group announced their plans to disband after the tour.