Netflix Debuts Aidan Turner's Accession to 'The Diplomat'

It is a truth that has not yet been universally acknowledged (but we're getting there) that the leaders of the U.S. and the U.K. governments are not always the brightest crayons in the box. Like most people who have the emotional wherewithal (and monetary means) to get elected to high office, those in positions of power tend to be petty, venial narcissists who have little moral compass and few strongly held values. This unspoken reality is one reason why The Diplomat achieved significant success when it originally debuted on Netflix in 2023. Set in the lavish world of the ruling class, it features lead characters who are so flawed that no one in their right mind would let them near high office, often doing incredibly short-sighted things that could destroy their countries, if not the planet.

The show's hilarious first season derived its charm from the chemistry between American lead Keri Russell (The Americans) and British actor Rufus Sewell (Victoria) as the toxically married Hal and Kate Wyld, a pair of ambitious political hustlers who had just recently traded off his cushy diplomatic posting to her country for her cushy diplomatic posting to his country. Continually on the verge of divorce, the Wylds have thus far survived for two seasons, despite a Hamlet-like penchant for everyone trying to secretly do each other in to get ahead.

However, Season 3 adds a new twist to the mix, as Hal accidentally happens to be on the line with the current POTUS when he inconveniently dies. With a significant power vacuum creating opportunities for advancement, the show has introduced a few new players to the series, giving everyone a chance to mix up their current status quo, both personally and professionally. Check out the trailer.

Here's the Season 3 synopsis:

Ambassador Kate Wyler is living the particular nightmare that is getting what you want. She just accused Vice President Grace Penn of hatching a terrorist plot and admitted she’s after the VP’s job. But now the President is dead, Kate’s husband Hal may have inadvertently killed him, and Grace Penn is the leader of the free world. None of this slows Hal’s campaign to land Kate the vice presidency. Kate steps into a role she never wanted, with a freedom she never expected, an increasingly complicated friendship with Foreign Secretary Austin Dennison, and an unnerving bond with First Gentleman Todd Penn.

The Diplomat features a blend of American and U.K. actors, led by Russell as Kate Wyle, Sewell as Hal, and Allison Janney (The West Wing) as former Vice-President, now-President Grace Penn.

The supporting ensemble includes returnees David Gyasi (The Sandman) as U.K. Foreign Secretary Austin Dennison, Rory Kinnear (Ridley Road) as U.K. PM Nicol Trowbridge, Ali Ahn (Agatha All Along) as CIA chief Eidra Park, Nana Mensah (Elementary) as White House chief of staff Billie Appiah, Michael McKean (Good Omens) as the late POTUS William Rayburn, Miguel Sandoval (Dirk Gently's Holistic Detective Agency) as U.S. Secretary of State Miguel Ganon, and Ato Essandoh (Altered Carbon) as Stuart Heyford.

Season 3 will also introduce Bradley Whitford (The Handmaid's Tale) as First Gentleman, Todd Penn; Celia Imrie (The Thursday Murder Club) as Margaret Roylin; and Aidan Turner (Rivals) as Callum Ellis. 

Debora Cahn serves as showrunner on Season 3 and lead writer for the series' scripts. Alex Graves is expected to helm multiple episodes again. Cahn, Graves, and Russell also executive produce alongside Janice Williams and Peter Noah.

The Diplomat Season 3 will premiere on Netflix with all episodes on Thursday, October 16, 2025. Seasons 1 and 2 are currently available to stream on Netflix. Season 4 is already greenlit.