If you’ve been watching War on HBO and noticed Serena Byrne’s growing baby bump, you’re not imagining things. Phoebe Fox was pregnant in real life during filming, and showrunner George Kay made the creative call to write her pregnancy directly into the show. The same wasn’t true for co-star Sienna Miller, whose real-life pregnancy was carefully hidden on camera. Here is everything we know about how War handled both pregnancies behind the scenes.
War is a legal drama anthology series created by George Kay, who’s best known for writing Lupin and Hijack. The first season follows the explosive divorce battle between international film star Carla Duval (Sienna Miller) and British tech billionaire Morgan Henderson (Dominic West). Ben Taylor, who directed Sex Education and Catastrophe, helms the show. Production companies New Pictures, Observatory Pictures, and Sky Studios produced the series for HBO/Max in the US and Sky Atlantic in the UK.
| Detail | On-Screen (War) | Real Life | How Production Handled It |
|---|---|---|---|
| Phoebe Fox (Serena Byrne) | Serena is pregnant with her first child alongside husband Nicholas Taylor | Fox was pregnant during filming (Sept 2025 – Feb 2026) | George Kay rewrote the scripts to include Serena’s pregnancy |
| Sienna Miller (Carla Duval) | Carla Duval is not pregnant in the show | Miller was 3 months pregnant at the start of filming, 35 weeks by wrap | Hidden with camera angles, wardrobe, and tight framing |
| Filming Dates | – | September 8, 2025 to February 2026 | Shot out of chronological order to manage both pregnancies |
| Miller’s Baby | – | Welcomed her third child in April 2026 | – |
Is Serena Byrne pregnant in War on HBO?
Yes. Serena Byrne is pregnant in War, and it wasn’t originally part of the plan. When Phoebe Fox told George Kay she was expecting, he decided to fold the pregnancy into Serena’s storyline rather than hide it or write around it.
What makes this interesting is how naturally the show treats it. Serena doesn’t suddenly become a “pregnancy story.” She’s still a sharp, aggressive lawyer running the high-profile Duval-Henderson divorce case alongside her husband and law partner, Nicholas Taylor (played by James McArdle). The bump is right there on screen, but the plot doesn’t revolve around it.
Kay and Fox wanted to normalize what that actually looks like on television: a woman doing her job while pregnant, without the pregnancy turning into a sideshow. Small real-life details even made it into the scripts, like Serena constantly snacking between meetings—a nod to Fox’s actual pregnancy cravings on set.
Why did George Kay write Phoebe Fox’s pregnancy into War?
George Kay didn’t have to do this. The standard TV playbook is to hide a pregnant actress behind desks, shopping bags, and clever camera angles. Kay went the other direction because he saw an opportunity.
“Look, it’s so rare to see a character on TV, a woman who is pregnant, and it is not the story.”
— George Kay, Decider interview (October 2026)
For Kay, the appeal was pretty straightforward. He could show a working woman at the top of her game who also happens to be expecting. In a show about London’s most cutthroat law firms, that felt authentic rather than forced. Women in these firms don’t stop working because they’re pregnant, and the show doesn’t pretend otherwise.
The fact that Fox’s pregnancy wasn’t planned from a writing standpoint actually gave the storyline a rawness that scripted pregnancies sometimes lack. There were no carefully plotted reveals or dramatic baby-related cliffhangers. Serena is just visibly pregnant while doing her job.
How did War hide Sienna Miller’s pregnancy during filming?
While Fox’s bump got the spotlight, Sienna Miller’s real-life pregnancy was a different production challenge entirely. Miller was roughly three months pregnant when filming kicked off in September 2025 at OMA X Film Studios in Enfield, East London. By the time the season wrapped in February 2026, she was 35 weeks along.
Because her character Carla Duval—an international film star going through a divorce—isn’t written as pregnant, the crew had to get creative. Director Ben Taylor and the wardrobe team used tighter camera framing, strategic costume choices, and careful shot composition to keep Miller’s bump hidden throughout the shoot.
Miller has been candid about how physically demanding the whole thing was. Speaking to The Observer, she described leaving for set and coming home in the dark during long production days, all while deep into her third trimester. She welcomed her third child in April 2026, roughly two months after production wrapped.
What was it like filming intimate scenes while pregnant?
One of the trickiest parts came during a love scene between Carla Duval and Jonathan “Johnny” Warren, played by Archie Renaux. Miller was about six to seven months pregnant at the time of filming.
She’s joked openly about the logistics. Being lowered onto a table with a noticeable bump while trying, in her words, to “feel sexy and not vom” wasn’t exactly a standard day on set. Renaux was reportedly terrified as well, navigating the physical staging with genuine concern for his co-star.
Miller also mentioned that she and Phoebe Fox would sit together between setups, eating snacks, bonding over their parallel pregnancies. Miller joked that Fox “got in first” with her announcement, and the two built a real camaraderie during the grueling schedule.
Who is Phoebe Fox?
Phoebe Mercedes Fox was born on April 16, 1987, in Hammersmith, London. Despite sharing a surname with Hollywood’s famous Fox family, she isn’t related to them. Her parents are both working actors—Stuart Fox and Prue Clarke.
Fox trained at the Royal Academy of Dramatic Art (RADA), graduating around 2010. She met her husband, American actor Kyle Soller (Andor, Bodies), while they were both students there. They married in 2010 and live in London.
Her screen credits include playing Marial in Hulu’s The Great (2020–2023), which earned the cast a Screen Actors Guild Award nomination. She also starred in The Woman in Black 2: Angel of Death (2014), Eye in the Sky (2015) alongside Helen Mirren, and appeared in Charlie Brooker’s Black Mirror in the episode “The Entire History of You” (2011). On stage, she earned a Laurence Olivier Award nomination for Arthur Miller’s A View from the Bridge in 2014.
Who are the cast members of War on HBO?
The first season of War features a deep ensemble of British and international talent:
- Sienna Miller as Carla Duval, the international film star filing for divorce
- Dominic West as Morgan Henderson, the tech billionaire husband
- Phoebe Fox as Serena Byrne, law partner at Taylor & Byrne, representing Carla
- James McArdle as Nicholas Taylor, law partner and Serena’s husband
- Nina Sosanya as Beatrice “Queen Bea” Ubosi, rival attorney at Cathcarts & Sons, representing Morgan
- Pip Torrens as St. John Smallwood, law partner at Cathcarts & Sons
- Archie Renaux as Jonathan “Johnny” Warren, an ambitious young lawyer
The supporting cast includes Emma Laird, Marisa Tomei, Kelly Macdonald, David Harewood, Richard Schiff, Nick Mohammed, and Celia Imrie.
Where was War on HBO filmed?
Filming took place entirely in and around London. The production’s home base was OMA X Film Studios in Enfield, East London. Location shooting spread across several recognizable parts of the city, including Smith Square in Westminster, the Southbank, and Canary Wharf’s corporate corridors.
The production also used residential and commercial spaces across Hertfordshire, supported by the Hertfordshire Film Office. The Columbia, an event space in Lancaster Gate, doubled as a character’s residence on the show. Production started on September 8, 2025, and wrapped in February 2026.
What is the plot of War on HBO?
War is set inside London’s elite legal world. The first season follows the divorce of Carla Duval and Morgan Henderson after ten years of marriage. What starts as a straightforward split turns into a full-blown legal war involving PR spin, weaponized tabloids, hidden assets, and psychological games. Their respective law firms—Taylor & Byrne and Cathcarts & Sons—stop at nothing to win.
The show is designed as an anthology. Future seasons will shift to entirely new cases and clients while keeping the competitive firm dynamics intact.
Will there be a Season 2 of War on HBO?
HBO hasn’t officially announced a second season of War yet. Given the anthology format, a renewal would likely bring a completely new case and potentially a fresh roster of guest stars, while the core law firm characters could carry over.
Did you watch War on HBO? Let us know what you thought about how they handled the pregnancy storylines in the comments below!
