Richard Ewing Powell (November 14, 1904 – January 2, 1963) was an American actor, singer, musician, producer, director, and studio head. Though he came to stardom as a musical comedy performer, he showed versatility and successfully transformed into a hardboiled leading man, starring in projects of a more dramatic nature. He was the first actor to portray private detective Philip Marlowe on screen.

From 1949 to 1953, Powell played the lead role in the NBC radio theater production Richard Diamond, Private Detective. His character in the 30-minute weekly show was a likable private detective with a quick wit. Many episodes ended with Detective Diamond having an excuse to sing a little song to his date, showcasing Powell's vocal abilities. Many of the episodes were written by Blake Edwards. When Richard Diamond came to television in 1957, the lead role was portrayed by David Janssen, who did no singing in the series. Prior to the Richard Diamond series, he starred in Rogue's Gallery. He played Richard Rogue, private detective. The Richard Diamond tongue-in-cheek persona developed in the Rogue series.