Simon Paisley Day (born 13 April 1967), also credited as Simon Day, is an English stage and screen actor. His most recent work includes Timon of Athens (2008), Entertaining Mr Sloane (2009), Private Lives (2010), Twelfth Night (National Theatre, 2011), The Taming of the Shrew (Shakespeare's Globe, 2012) and portraying Sir Cosmo Duff Gordon in the 2012 ITV mini-series Titanic.