Sienna Miller is heading into a very different kind of battle in WAR, the new legal drama from George Kay, the creator of Lupin and Hijack. The series puts Miller opposite Dominic West in a high-profile divorce case that quickly becomes a much bigger fight between two powerful London law firms.
With the official trailer now released, searches for War Sienna Miller are picking up, and there is plenty to know before the series premieres.
Here is everything we know about WAR, including its release date, Sienna Miller’s character, cast, story, trailer, and where to watch.
When Is WAR Coming Out?
WAR premieres on October 2, 2026.
In the UK, the eight-part series will premiere on October 2, 2026, on Sky and the streaming service NOW. New episodes will be released weekly.
In the U.S., WAR will air on HBO and stream on HBO Max, while HBO Max will also carry the series in Australia.
The series has already received a two-season order, with Season 2 currently in production. The second season will introduce a new legal case and a different group of central characters.
What Is WAR About?
WAR is a legal drama set inside two rival London law firms: Cathcarts & Sons and Taylor & Byrne.
The first season centers on the explosive divorce of tech entrepreneur Morgan Henderson, played by Dominic West, and international film star Carla Duval, played by Sienna Miller.
As the two sides prepare for a major legal battle, the lawyers representing them become just as invested in the case as their wealthy clients. Ambition, professional rivalry, and personal relationships begin to collide as the divorce turns into a major public battle.
At the center of the story is also young lawyer Jonathan “Johnny” Warren, played by Archie Renaux. His involvement in the case pulls him into the competitive world of London’s legal elite.
The legal-drama setup should also appeal to viewers following other courtroom-focused shows, including The Rainmaker Season 2, which returns with another high-stakes legal story in October.
Sienna Miller’s Role in WAR
Sienna Miller plays Carla Duval, an international film star whose marriage to tech entrepreneur Morgan Henderson has broken down.
The divorce between Carla and Morgan is the central legal case of Season 1. Their personal problems quickly become a professional battle between the two rival law firms representing them.
Miller stars opposite Dominic West, who plays her estranged husband.
The actress is known for projects including Anatomy of a Scandal and American Sniper, while West is known for The Wire and The Crown.
WAR Cast: Who Stars With Sienna Miller?
The main cast includes:
- Sienna Miller as Carla Duval
- Dominic West as Morgan Henderson
- Archie Renaux as Jonathan “Johnny” Warren
- Phoebe Fox as Serena Byrne
- James McArdle as Nicholas Taylor
- Nina Sosanya as Beatrice “Queen Bea” Ubosi
- Pip Torrens as St John Smallwood
The wider cast includes Celia Imrie, Nick Mohammed, Emma Laird, Aran Murphy, Archie Panjabi, Adrian Scarborough, Shaheen Jafargholi, Akiya Henry, Honor Swinton Byrne, Miles Jupp, Kartanya Maynard, Alexandra Mardell, Dylan Edwards, Mark Quartley and Steve Furst.
Who Created WAR?
WAR comes from George Kay, the creator, writer and executive producer behind Lupin, Hijack and The Long Shadow.
The series is directed by Ben Taylor, whose previous credits include Sex Education and Catastrophe.
The series is produced by New Pictures and Observatory Pictures in association with Sky and HBO.
What Is the WAR Story Really About?
On the surface, WAR is about a divorce.
But the story also looks at what happens when a highly public personal dispute becomes a major legal and professional battle.
Carla Duval and Morgan Henderson have the money, status, and public attention to turn their separation into a headline-making case. Their lawyers, meanwhile, are fighting for their clients while competing with rival firms that are equally determined to win.
That creates several layers to the story: the divorce itself, the rivalry between the law firms and the younger lawyers trying to establish themselves inside this high-pressure environment.
Sky describes the series as a returning legal drama set around two prestigious rival London law firms, with ambition, betrayal and high-stakes courtroom battles at the center.
WAR Official Trailer
The official WAR trailer was released on September 17, 2026, giving viewers a closer look at Sienna Miller and Dominic West in the series.
The trailer focuses on the increasingly bitter divorce battle between Carla and Morgan while showing the lawyers preparing to fight for their respective clients.
You can watch the official WAR trailer on Sky Group.
The trailer’s release comes just weeks before the series begins, making September an important period for searches around WAR, Sienna Miller, the cast, and the release date.
How Many Episodes Does WAR Have?
Season 1 of WAR has eight episodes.
The episodes will be released weekly on Sky and NOW in the UK, beginning October 2.
Rather than dropping the entire season at once, the weekly schedule gives the legal battle room to develop across the eight episodes.
Will There Be a WAR Season 2?
Yes.
WAR was ordered for two seasons, and Season 2 is already in production.
The format of the series means Season 2 will move to a new legal case with different claimants and characters, rather than simply continuing the Season 1 divorce case.
Sky has confirmed that the returning legal drama will introduce a different case for its second season, although more details about the story are still being revealed.
Where Can You Watch WAR?
The availability depends on your location.
United Kingdom: WAR premieres on Sky and NOW on October 2, 2026.
United States: The series will air on HBO and stream on HBO Max.
Australia: WAR will stream on HBO Max.
Sky also lists availability through Sky/WOW in Germany, Switzerland, and Austria.
For the latest availability information, you can also check the official WAR page on Sky.
Is WAR a Movie or a TV Series?
Despite searches such as “Sienna Miller War movie,” WAR is a TV series, not a movie.
It is an eight-part legal drama produced as a Sky Original, with HBO involved in its international rollout. The first season follows the divorce case involving Carla Duval and Morgan Henderson.
That distinction matters if you’re searching for War Sienna Miller, because most of the relevant information is about the upcoming television series rather than a standalone film.
Why Is Everyone Searching for Sienna Miller and WAR?
The timing is important.
Sky released the full official trailer on September 17, 2026, less than three weeks before the October 2 premiere.
Miller is also one of the two central stars alongside Dominic West, while the story itself gives her character Carla Duval a major role in the season’s main legal conflict.
That combination explains why searches around War Sienna Miller, the cast, and the show’s release date are becoming more noticeable as the premiere approaches.
WAR Quick Facts
DetailInformation
Series WAR
Genre Legal drama
Release Date October 2, 2026
Episodes 8
Creator George Kay
Sienna Miller Carla Duval
Dominic West Morgan Henderson
Archie Renaux Jonathan “Johnny” Warren
UK Platform Sky / NOW
U.S. Platform HBO / HBO Max
Season 2 Ordered and in production
Final Thoughts
WAR brings together Sienna Miller, Dominic West and George Kay for a legal drama built around a high-profile divorce and the rival law firms fighting over it.
The first season has eight weekly episodes, beginning October 2, 2026, while the series has already been renewed for a second season with a new legal case.
For anyone searching for War Sienna Miller, the key details are simple: Miller plays international film star Carla Duval, Dominic West plays her estranged husband Morgan Henderson, and their divorce becomes the center of a much larger legal battle between two London firms.
With the official trailer now out, the next major date is October 2, 2026, when WAR begins its weekly run on Sky and NOW in the UK, with HBO and HBO Max handling the U.S. release.