Ian McDiarmid (; born 11 August 1944) is a Scottish actor and director of stage and screen. Making his stage debut in Hamlet in 1972, McDiarmid joined the Royal Shakespeare Company in 1974, and has since starred in a number of Shakespeare's plays. He has received an Olivier Award for Best Actor for Insignificance (1982) and a Tony Award for Best Featured Actor in a Play for Faith Healer (2006).
He gained prominence for portraying Emperor Palpatine / Darth Sidious in the Star Wars franchise starting from Return of the Jedi (1983). He also acted in Gorky Park (1983), Dirty Rotten Scoundrels (1988), Restoration (1995), Sleepy Hollow (1999), and The Lost City of Z (2016).
Source : Wikipedia
