The fourth season of The Diplomat is now available in full on Netflix, with its eight episodes revealing one of the production's best-kept secrets: the addition of Jodie Whittaker, known for Doctor Who and Broadchurch, to the show's cast. Her presence was kept hidden for much of the pre-premiere promotion.
Whittaker was only listed as a guest star for the season, alongside Celia Imrie, Miguel Sandoval, Rosaline Elbay, and Aidan Turner, and had a very brief appearance in the official trailer, right toward the end. However, her character becomes a key plot point in the second half of the season.
Below are details on who the character is, how she fits into the new season, and what Keri Russell has said about her arrival on the show. Warning: the following content includes spoilers for The Diplomat season 4.
Who does Jodie Whittaker play in The Diplomat season 4?
Jodie Whittaker plays Bethan Vaughan, who becomes the new Prime Minister of the United Kingdom. Her arrival in office is a direct consequence of the cliffhanger that closed season 3, the repercussions of which shake Downing Street from the beginning of the new episodes.
In episode 4, Nicol Trowbridge, played by Rory Kinnear, announces his resignation, ending his tenure as the only Prime Minister the series has had since its 2023 premiere. After a long and contested leadership battle, Vaughan prevails over a particularly unpleasant rival, thus becoming the second person to hold the office in the entire series.
The character is initially presented as an unknown. According to the official Netflix description, Bethan Vaughan is, at least on paper, the perfect counterpart to Kate.
As is often the case in The Diplomat, the arrival of a new face at Downing Street brings a new set of complications for Kate and the Penn administration. Vaughan is not easily intimidated and is not willing to automatically align herself with Washington, especially after how her closest ally treated her predecessor.
The show's executive producer, Janice Williams, explained in a TUDUM piece: On the surface, there is a lot in Vaughan that reminds you of Kate, adding that she believes it was Jodie Whittaker herself who brought that connection to the character, with the idea of two determined women making their way in a man's world and taking it all on together.
Why did The Diplomat change Prime Ministers?
The show's creator, Debora Cahn, explained to Deadline that the fiction had reached a point where the UK imagined by the series had kept the same Prime Minister and the same Foreign Secretary for longer than the real UK had gone through several changes of government. According to Cahn, it felt dishonest not to force the characters to face what happens when all the relationships built are suddenly reset and you have to start over.
Cahn managed to keep Whittaker's casting a secret until the very day of the premiere.
Keri Russell told Deadline that she was curious to know who would be chosen to play the new character once it was written. According to Russell, Cahn wanted the new Prime Minister to be an equal to Kate, not a superior, as that role is already occupied by Grace Penn, played by Allison Janney. The idea was to show a woman of Kate's generation exercising power with ease and projecting a confidence that Kate has not yet fully reached.
Russell was full of praise for the final result, highlighting how well Whittaker played the role. Early reviews seem to agree with that assessment.
Where have you seen Jodie Whittaker before?
Jodie Whittaker is primarily known for becoming the first woman to play the Doctor in Doctor Who, starring as the Thirteenth Doctor between 2018 and 2022. Before that, she played grieving mother Beth Latimer alongside David Tennant and Olivia Colman in the three seasons of ITV's Broadchurch.
Her other credits include Attack the Block, the Black Mirror episode The Entire History of You, Trust Me, Time, One Night, and more recently, her standout performance in Toxic Town for Netflix.
Frequently asked questions about The Diplomat season 4
Who plays the new Prime Minister in The Diplomat season 4?
Jodie Whittaker plays Bethan Vaughan, the new British Prime Minister who replaces Nicol Trowbridge following his resignation in episode 4 of the season.
Why does Nicol Trowbridge resign in The Diplomat season 4?
Rory Kinnear's character announces his resignation as a direct consequence of the repercussions of the cliffhanger that ended season 3, which triggers a contested leadership battle for the office of Prime Minister.
How does Jodie Whittaker’s character relate to Kate in the series?
According to executive producer Janice Williams, Bethan Vaughan shares several traits with Kate, showing herself to be a determined woman making her way in a male-dominated environment, which creates a particular connection between both characters.
Was Jodie Whittaker’s participation in the series kept secret?
Yes, creator Debora Cahn managed to keep Jodie Whittaker's casting hidden until the day of the season 4 premiere, appearing only as a guest star and with a brief appearance in the official trailer.
What other productions has Jodie Whittaker participated in?
Jodie Whittaker is known for playing the Thirteenth Doctor in Doctor Who and for her role in Broadchurch. She has also participated in Attack the Block, the Black Mirror episode The Entire History of You, Trust Me, Time, One Night, and Toxic Town.
