Immigrated to the USA (Brooklyn) at age 9, adding the decorative initials to his name some time later. Diamond moved to Hollywood in 1941, working on mostly unexceptional films before teaming up with Billy Wilder for "Love in the Afternoon" (1957). He became Wilder's co-writer of choice (taking the place of Charles Brackett), with the team turning out consistently incisive, outstanding comedies through the director's last film, "Buddy, Buddy" (1981).