Ben Hardy (Simon) and Jessica Plummer (Emma) were a couple in real life.
The house in The Girl Before is not actually real and was created for the show. The exterior of the mansion was set up in Redlands, Bristol and was designed to look like vertical planks of wood.
The church he takes them to visit for its architecture is St Stephen Walbrook, Bank, London.
Based on the novel by JP Delaney.
Gugu Mbatha-Raw and David Oyelowo previously stared together in The Cloverfield Paradox (2018).