Here's what to know about Aidan Turner, the actor who stars opposite Keri Russell as Kate Wyler's "bird watcher" beau Callum Ellis in 'The Diplomat' season 3.. Callum Ellis's function in The Diplomat Season 3 has been that of bare controversy, and people have questioned if he might be a double agent. Callum is a spy and British negotiator and is also a main character in political and personal intrigues, most significantly his illicit affair with Kate Wyler.
Aidan Turner: Callum Ellis The Diplomat Aidan Turner credited as playing. Callum Ellis. Meet Aidan Turner, the Irish Actor Who Plays Callum Ellis in 'The Diplomat' Season 3 Kate Wyler has a new love interest, and you may recognize him from a beloved historical drama. Netflix's hit.