Jack Gleeson and James Nesbitt have joined the cast of Hercule, the BBC and BritBox adaptation that puts a young Hercule Poirot front and centre. The six-part series begins filming imminently in Liverpool, with Edward Bluemel confirmed in the title role.

The Hollywood Reporter broke the casting news on 4 August 2026, naming Gleeson — best known as King Joffrey Baratheon in Game of Thrones — and Nesbitt, whose credits span The Missing and Bloodlands, alongside Bluemel. The BBC had first confirmed Bluemel's casting back in June, noting his prior work in We Might Regret This and My Lady Jane (BBC Media Centre).

The ensemble rounds out with Henry Ashton, James D'Arcy, Calvin Demba, Phil Dunning, Tamsin Greig, Guy Remmers, Rebecca Rittenhouse and Mawaan Rizwan (The Hollywood Reporter).

Benji Walters, who wrote Code of Silence, scripts the series. The BBC describes it as following Poirot's first cases, while the production's own logline calls it "an intimate study of Hercule Poirot the man, and an epic portrait of Britain between the wars." The show draws on three of Agatha Christie's early stories and introduces Poirot to future friends, allies and one particular nemesis.

Jonny Campbell directs the first two episodes. Chanya Button takes episodes three and four, and Alrick Riley closes out the final pair. Charlie Palmer serves as series producer. Executive producers include Walters, Campbell, James Prichard, Rebecca Durbin, Damien Timmer, Nick Lambon, Robert Schildhouse, Jon Farrar and Stephen Nye.

Mammoth Screen and Agatha Christie Limited produce the series for BBC iPlayer and BBC One in the UK, with BritBox carrying it in North America. Fifth Season handles global distribution. The series is expected to arrive in 2027.

For fans, the draw is straightforward: a beloved detective's origin story, a sizeable ensemble, and Liverpool standing in for interwar Britain. The creative team behind it has a clear brief — find the man before the moustache became legend.