Garth Brooks has joined the lineup for a benefit concert to raise money for a Martin Luther King Jr. memorial in Washington, D.C. The Sept. 18 show at New York's Radio City Music Hall will also feature Queen Latifah, Kenny "Babyface" Edmonds, Stevie Wonder, Aretha Franklin and Carlos Santana. Tickets go on sale July 30. Approximately $81 million has already been raised, but a total of $100 million is needed to complete the memorial. Set to be completed next year, it will be located on the National Mall between the Lincoln and Jefferson memorials.