Kate Wyler is a seasoned US diplomat who spent her career working behind the scenes in war-torn regions to make the world a better place. Now she’s in the limelight as US ambassador to the United Kingdom. In Season 3 she must step even further into the public eye to keep the White House — and her personal life — intact, following the sudden death of the sitting president. Despite their rocky introduction, can new president Grace Penn prove to be an ally? 

“This season, [Kate’s] getting Grace into the position of the presidency and getting her safe,” Russell tells Tudum. “And at the same time, Kate’s dealing with Hal and what he might’ve done and the implications of his involvement.” 

As we see in the Season 2 finale, Hal is the last person to speak with President Rayburn alive. Despite the high stakes of this latest political catastrophe, Kate is exactly where she wants to be. “What was fun for me was getting to do what Kate does really well: be second in command and be the supporter of someone important, versus giving speeches and doing the front of the line kind of things,” Russell says.

The Americans, Cocaine Bear,  and Felicity

Hal Wyler is Kate’s charismatic husband and a legendary diplomat in his own right. He’s negotiated the end of wars but made a lot of enemies along the way through ruthless means. Standing outside the spotlight and letting his wife shine doesn’t come naturally to Hal. And considering his connection to President Rayburn’s death, Hal may no longer be allowed to sit on the sidelines. 

“It’s straight into the CIA [for Hal]  — the debriefing, trying to find out exactly what happened, what was said, and who was in the room,” Sewell tells Tudum. “If you’re playing someone who’s confident … it’s really good to get to play them absolutely rattled. You get to see another side of all of us. It’s unbelievably chaotic.” 

While this tense new dynamic would terrify most people, Hal isn’t most people. As The Diplomat Seasons 1 and 2 have proven, the other Ambassador Wyler always manages to land on his feet. But how will he pull off his charm offensive this time?  

Scoop, Kaleidoscope,  and The Holiday.

 Meet President Grace Penn, the new leader of the free world. Grace enters her role in the most dire of positions: Her predecessor  dies suddenly, she’s an ocean away from home, and the Wylers know Grace is the person who set the fatal HMS Courageous attack into motion.   

Grace kicks off the third season running — literally. “When we pick up in Season 3, there’s no time lapse. It’s just a direct cut from me running with the Secret Service, them grabbing me, and us running up that long field and into the house,” Janey tells Tudum. 

The action doesn’t stop there for Grace, who must settle into her presidency … while dealing with the threat that the Wylers represent. However, she does come to some surprising realizations, explains creator Cahn. “Grace would love to be hating Kate, but then it turns out Kate happens to have better advice than anybody else in this situation,” the showrunner — and Emmy-nominated West Wing writer — explains. “So Grace, despite herself, finds herself looking to Kate for guidance about what her next move should be.”

The West Wing, I, Tonya,  and Lou

The Diplomat viewers have heard about Grace’s mysterious husband, Todd Penn, since Season 1. Now they finally get to meet him. 

“I was thrilled when I heard that Debora was interested in me doing something. I had no idea what it was, and I love the show,” Whitford — who worked with Cahn on The West Wing — tells Tudum. Eventually, the Emmy-winner actor learned he would play the new First Husband of the United States, reuniting him with his West Wing co-star Janney. 

Although the world is focused on Grace’s ascent to power, Todd is evolving right alongside her. “Todd’s making a big adjustment in his life with not a lot of grace, enthusiasm, or warning,” Whitford says. “The thing that I love about this show is the diplomacy is always just amplified and resonating with what’s going on personally. That’s really fun. There’s a power dynamic [between Grace and Tood]. There’s negotiation.” 

The West Wing, The Madness, and the upcoming series Death by Lightning 

Stuart Hayford is Kate’s deputy chief of mission at the US Embassy in London. He’s her savvy right-hand man, nudging her in the right diplomatic directions as needed. He’s also a former DC campaign manager with deep connections in the White House. 

Essandoh says Season 3 kicks off with one simple word: “Pandemonium.” While presidents have died before, “this is one of those unexpected things that when I read the script, I had no idea it was coming,” the actor tells Tudum. 

Stuart must rise to the occasion with his boss, as Kate finds herself on a new rung of power. “There’s no time to breathe in the narrative,” Essandoh says. ”

Chicago Med, Reptile, and Altered Carbon

Eidra Park is the chief of the CIA station in London, one of the largest CIA hubs in the world. She manages the very close, very important, and very complicated relationship between the CIA and MI6 and is responsible for relaying intelligence information to Kate’s team. While initially suspicious of Kate, she eventually warms to her.

“I talked to a couple consultants — women who used to work within the CIA and were chiefs of stations,” says Ahn on her prep for the role. “Then I read some memoirs [by] people who lived their life undercover, which were basically things that Eidra would’ve done before she got to this job.” 

Like the rest of her colleagues, Eidra must weather a continuously shifting political landscape. “Eidra’s somebody who compartmentalizes her feelings, and I don’t think that’s really changed. I think that’s what makes her good at her job. But the difference is that each season has tested how able she is to keep compartmentalizing her feelings,” Ahn tells Tudum. Season 3 serves up Eidra’s biggest curveball yet. 

“In Season 3, work isn’t going so well. I feel like that’s a first for her,” Ahn says. Can she turn things around before it’s too late?   

Agatha All Along, Raising Dion, and Supernatural

Austin Dennison is the British foreign secretary under Prime Minister Trowbridge. Weighed down by his struggle to rein in his brash head of government, Dennison and Kate come to rely on each other as unexpected allies — and maybe something more. Although their relationship is always one dilemma away from being completely flipped on its head.  

“At the end of Season 2, Dennison’s like, ‘I want nothing more to do with you, Kate. I am second in command to this guy and my country,’ ” Gyasi tells Tudum. “In Season 3, we pick right up where we left off.” 

And, the death of Rayburn instantly makes Dennison rethink his feelings about Kate. “It’s funny, when someone or a person or a nation is dealing with loss, the head goes out of the window,” Gyasi explains. “Suddenly Dennison is speaking much more from his heart with Kate.” 

Interstellar, Half Bad: The Bastard Son & The Devil Himself, and Troy: Fall of a City 

Nicol Trowbridge is the prime minister of the United Kingdom. Foul-mouthed and volatile, Trowbridge never questions his own war hawk mentality. That’s Dennison’s (exhausting) job. Following the death of Rayburn, Trowbridge must determine what his new relationship with the United States — and its new heads of state — will be. 

Creator Cahn is in awe of Kinnear’s talents as Trowbridge. “Director Alex Graves calls Rory Kinnear the Stradivarius. He can do anything, and he does it at such a level of skill and excellence that it’s just mind-boggling,” Cahn says.” When Rory’s working, a lot of us sit there asking for more takes just so that we can watch him perform, like we’re at the theater or something — like we bought a ticket and now we get to see what he does over and over again.”

The Bank of Dave films, Toxic Town, and Black Mirror  (as yet another prime minister)

Margaret Roylin is like political kryptonite in The Diplomat — potentially radioactive to the touch, but irresistible up close. She was the prime minister’s former — and unofficially current — adviser whose shrewdness is to be envied, no matter which party you support. 

As a key figure in the planning of the HMS Courageous explosion, Roylin’s choices will continue to send shockwaves through The Diplomat’s delicate political ecosystem. 

Thursday Murder Club, Good Grief, and Malevolent 

This enigmatic Brit — a bit of a “bird watcher” — manages to charm Kate. Callum holds vital information. 

Cahn says Turner “immediately just fit” into the Diplomat ecosystem. He shared his first scene — found in Episode 5 — with series leads Russell and Sewell. “Those were tense scenes, and Aidan was just right at home,” Cahn says. “He just dove into the deep end and had no trouble swimming. The three of them had such a great time working together.” 

Russell adds that Turner is “a delight” to work with, and thinks Kate responds to him because he’s unlike her husband in many ways. “Hal is a real force, which is what is so attractive about him,” says Russell. “And I think Callum has a very different energy and speed.” 

Poldark, the Hobbit films, and Rivals

This Diplomat newcomer has caught the eye of a very powerful person on the international stage. 

“Tracy is absolutely just delightful on screen,” says Gyasi of his new costar.

The Pitt, Twilight of the Gods, and Treason

The prime minister’s wife, Lydia, enters the Diplomat’s political playing field in Season 2. She’s one of the women who has sway over her husband’s chess moves. 

“Once you get to the top, the ground beneath you becomes shakier, and you realize it’s a lonely business up there,” Kinnear says of Trowbridge. “We meet his wife … and we see how the people closest to him impact his decision-making.”

But the Trowbridges’ bond is not only on-screen. Colin and Kinnear are partners in real life as well.

Penny Dreadful, Eric, Master of None

Billie Appiah is the White House chief of staff. Tenacious and a skilled fixer, she and Stuart used to run campaigns together. So Billie often relies on Stuart’s judgment. Although she often appears unflappable, the death of  father figure President Rayburn will reveal a new side of Billie, Mensah tells Tudum. 

“I was super excited because Billie is not someone who has exhibited a lot of emotion thus far in The Diplomat, and at the top of Season 3 you finally get to see her underbelly exposed,” Mensah explains. “That was exciting to play. I think it will also be exciting for audiences — and destabilizing. It's like, ‘Wait, what? Billie has emotions? Besides being mildly irritated?’ ”

The Chair,13 Reasons Why, and Bonding 

Miguel Ganon is the US secretary of state. Ambitious in his own right, Ganon disapproves when Kate goes rogue to get the job done… And he’s not exactly thrilled with her choice of husband, either.

Sewell says Ganon is inadvertently part of the cause of President Rayburn’s death, since Hal originally planned to share Grace’s indiscretions with Ganon, not the president. “[Hal] tells the president directly for fear of how that news would be given to him to someone else’s advantage,” he says. “What I can’t predict is that [the president will] drop dead from the news.” 

Station 19, Blow, and Social Distance 

The vice president’s chief-of-staff Nora is suddenly much busier in The Diplomat Season 3. 

Kaleidoscope, Qabeel, and Ramy

Ivy is the head of President Penn’s Secret Service detail. She is now in charge of protecting the most important American politician in the world. 

Orange Is the New Black, Younger, Ms. Marvel

In Seasons 1 and 2, President Rayburn is an aging but competent leader trying to restore America’s position on the world stage.

Better Call Saul, Grace and Frankie, and Clue

Cecilia Dennison views politics as her brother Austin’s domain. When we meet the stylish firecracker midway through Season 1, she’s residing with Austin, whose devotion to his sister runs deep.

Sex Education, The Haunting of Bly Manor, and The Fall of the House of Usher