David Bruce Cassidy (born April 12, 1950) is an American prolific character actor of stage, singer and guitarist. He is best known for his role as Shirley Jones's eldest son, Keith Partridge, in the 1970s musical/sitcom The Partridge Family from 1970 to 1974 (ironically, Jones is Cassidy's stepmother in real life.) He enjoyed a successful pop career in the 1970s, and still performs today.