David Bruce Cassidy (April 12, 1950 – November 21, 2017) was an American actor, singer, songwriter, and guitarist. He was best known for his role as Keith Partridge, the son of Shirley Partridge (played by his stepmother, Shirley Jones), in the 1970s musical-sitcom The Partridge Family. This role catapulted Cassidy to teen idol status as a superstar pop singer of the 1970s.

Source: Wikipedia (https://en.wikipedia.org/wiki/David_Cassidy)