Stephen Dillane (born 30 November 1956) is a British actor experienced with roles on both stage and screen. He is arguably best known for his Emmy-nominated performance as Thomas Jefferson in the HBO mini-series John Adams. He has also appeared as Leonard Woolf in The Hours, Merlin in King Arthur and Horatio in the Mel Gibson-starring version of Hamlet.
His son, actor Frank Dillane, portrays the teenage Lord Voldemort in the film adaptation of Harry Potter and the Half-Blood Prince.
In Game of Thrones Dillane is playing the role of Stannis Baratheon. He was announced in the role on 19 July 2011. He is a new starring cast member for the second season.