John Ronald Simm (born 10 July 1970 in Leeds, West Riding of Yorkshire) is an English actor and musician. He grew up mainly in Lancashire. His roles include two BAFTA award-winning BBC Wales dramas: as Sam Tyler in the drama Life on Mars and as the Master in the long-running science fiction series Doctor Who. He has appeared in many popular television dramas such as The Lakes, State of Play and two BAFTA award-winning serials; Clocking Off and Sex Traffic. His movie roles include Human Traffic and 24 Hour Party People. He was nominated for the Olivier and Theatergoer's Choice Award for the best Actor 2008.
Besides acting, Simm was a founding member, songwriter and guitarist with the rock band Magic Alex.