McCormack will play Jane Swire, the wife of Firths character Dr Jim Swire.
Maryam Hamidi (Vigil) is guest writer on an episode.
Otto Bathurst (Peaky Blinders) serves as lead director.
Catherine McCormack and Colin FirthRoss Ferguson/Mariano Vivanco
Jim Loach (Save Me) will also direct an episode.
Other EPs include David Harrower, Liz Trubridge, Jim Sheridan, Kirsten Sheridan, and Oskar Slingerland.
Brian Kaczynski is producer and Maryam Hamidi is also associate producer.
