"McDiarmid has worked as an actor and director in British theatre.He has starred in several Shakespeare plays, including "Hamlet" (1972), "The Tempest" (1974, 2000), "Much Ado About Nothing" (1976), Trevor Nunn's 1976 "Macbeth" (television 1978), "The Merchant of Venice" (1984), and "King Lear" (2005).