Nana Mensah will be a series regular in The Diplomat Season 4. The actor has played Billie Appiah, the White House Chief of Staff, since Season 1.
Mensah joins Allison Janney (Grace Penn) and Bradley Whitford (Todd Penn), who have also been upped to series regulars in the fourth season, which is set to start filming this fall. The Diplomat Season 3 came out in full on October 16 on Netflix. Mensah’s promotion was announced by Deadline on November 4.
Mensah’s Billie started as Chief of Staff to President William Rayburn (Michael McKean). She was fiercely loyal to Rayburn and was one of the people trying to oust his vice president, Grace Penn (Janney), from her office earlier in the series. The plan was to replace Penn with U.K. Ambassador Kate Wyler (Keri Russell), but fate had other plans. Billie found herself serving as Penn’s Chief of Staff after the sudden death of Rayburn, who died while on the phone with Kate’s husband, Hal Wyler (Rufus Sewell), as he delivered the distressing news about Penn’s involvement in the strike on the British ship in the Persian Gulf.
West Wing alums Janney and Whitford have been guest stars in the Emmy-nominated political drama until now. Janney first debuted in Season 2 as vice president Grace Penn. Grace became president in the Season 2 finale, and the aftermath of her ascension will be seen in the Season 3 premiere. Whitford made his debut in the third season as Todd Penn, Grace’s husband, who is now the first gentleman.
Here’s everything we know about The Diplomat Season 4. (Take a deep dive into The Diplomat Season 3 finale in our interviews with cast and creators.)
Is The Diplomat renewed for Season 4?
The Diplomat was renewed for Season 4 on May 12. Season 3 consists of eight episodes.
When does The Diplomat Season 4 premiere?

Netflix
The Diplomat Season 3 comes out in full on Thursday, October 16. The Diplomat Season 4 starts filming this fall. A release date will be announced at a later time.
What happens in The Diplomat Season 3?
In Season 3 of The Diplomat, Ambassador Kate Wyler (Keri Russell) lives the particular nightmare that is getting what you want. She just accused Vice President Grace Penn (Janney) of hatching a terrorist plot and admitted she’s after the VP’s job. But now the President is dead, Kate’s husband Hal (Rufus Sewell) 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 (David Gyasi), and an unnerving bond with First Gentleman Todd Penn (Whitford).
“Everything we learned about Grace Penn at the end of Season 2 makes the relationship between the U.S. and the U.K. a lot more complicated going forward now that she’s president,” creator/executive producer Deborah Cahn told TV Insider. “Getting rid of her is not really viable in the same way…or maybe it is.”
Who is in The Diplomat cast?
In addition to Russell, Sewell, Janney, Whitford, and Gyasi, The Diplomat stars Ali Ahn, Rory Kinnear, and Ato Essandoh. Rivals star Aidan Turner is also in Season 3 in a recurring role.
The series is created by showrunner/executive producer Cahn and is executive produced by Russell, Janice Williams, and Alex Graves.
The Diplomat, Season 4 Premiere, TBA, Netflix
More Headlines:
- ‘The Diplomat’: Nana Mensah Upped to Series Regular for Season 4
- ‘Survivor 49’ Sneak Peek: Kele Plans a Big Move Right Before Merge (VIDEO)
- ‘Crutch’: Tracy Morgan Talks ‘The Neighborhood’ Spinoff Show & its Special Tribute to His Late Wife
- ‘Bargain Block’s Keith Bynum Teases New ‘Projects’ After HGTV Show Cancellation
- Is Sig Hansen Leaving ‘Deadliest Catch’? Everything He’s Said About His Future



(0) comments
Welcome to the discussion.
Log In
Keep it Clean. Please avoid obscene, vulgar, lewd, racist or sexually-oriented language.
PLEASE TURN OFF YOUR CAPS LOCK.
Don't Threaten. Threats of harming another person will not be tolerated.
Be Truthful. Don't knowingly lie about anyone or anything.
Be Nice. No racism, sexism or any sort of -ism that is degrading to another person.
Be Proactive. Use the 'Report' link on each comment to let us know of abusive posts.
Share with Us. We'd love to hear eyewitness accounts, the history behind an article.