Ian McDiarmid is a Scottish actor and theatre director, who has also made sporadic appearances on television, and appeared in 47 films since 1976. Internationally, he is arguably most famous for his role as Palpatine/Darth Sidious in the Star Wars saga, which he reprised in The Rise of Skywalker, the final installment in the Star Wars sequel trilogy and in the Disney+ original series Obi-Wan Kenobi. He also played Brother Jacobus in Dragonslayer and Ambrose in Restoration. Archive recordings of him can be heard in the Star Wars: The Clone Wars episode "Shattered" and in the Star Wars: The Bad Batch episode "Aftermath".
McDiarmid also portrayed Professor Levi in The Young Indiana Jones Chronicles episode "Paris, October 1916" (later edited into The Adventures of Young Indiana Jones: (Chapter 9) "Demons of Deception").