What happens when a crime writer and an actress get together for a little romance – and a bit of murder?

Fans of Agatha Christie mysteries have definitely heard of her Tommy and Tuppence series, which was launched over 100 years ago in her novel The Secret Adversary. BritBox, a streaming service that focuses almost exclusively on British detective series, is launching a six-part mini-series covering the couple’s exploits, based on the books and short stories featuring them.

The streamer announced Tuesday that it has completed casting for Agatha Christie’s Tommy & Tuppence, which will premiere next year. Alex Jennings of The Crown and You actress Saffron Burrows join the show as guests. Antonia Thomas (The Good Doctor) will play Prudence (Tuppence) Beresford, Josh Dylan (The Buccaneers) stars as Thomas Beresford, and veteran actor Imelda Staunton will play Aunt Ada, a private detective who joins the couple in their exploits.

Callie Cooke (F1) will play Det. Sgt. Draper, Nicholous Richardson stars as Julius, a film producer, Charlie Condou from Doctor Who plays a pub landlady and Chizzy Akudolu plays Det. Inspector Merriot. Other guest stars will include Sebastian De Souza (The Life List), Sean Pertwee (The Hack), Denise Black (Rivals), and Alice Krige.

Tommy & Tuppence will reimagine the Beresfords in the modern world, something that Christie herself did with each subsequent adventure. After The Secret Adversary, T and T appeared in the 1929 short story collection Partners in Crime, the 1941 novel N or M?, the 1968 novel By the Pricking of My Thumbs, and 1973’s Postern of Fate.

Tommy and Tuppence have appeared in numerous television adaptations over the years, most recently starring David Walliams and Jessica Raine in Partners in Crime, the 2015 BBC series, also available on BritBox.

Phoebe Eclair-Powell is writing the series. She said in a statement, “Christie’s detective duo are witty, sharp, and raring to solve lots and lots of murders whilst asking if they should really be more than just Partners in Crime… To bring Tommy and Tuppence into the 21st Century is truly an honor.”