The Modern Jazz Quartet was formed in 1952 by Milt Jackson (vibraphone), John Lewis (piano, musical director), Percy Heath (bass), and Kenny Clarke (drums). Connie Kay replaced Clarke in 1955. Various of the members had played together backing other artists such as Dizzy Gillespie and Ray Brown, and in Jackson's own Quartet. Through their long existence, they have worked with Classical musicians and are known for incorporating elements of Classical music into jazz, being one of the most notable examples of the style called Third Stream.