Lolly Adefope, Timothy Spall, Joanna Scanlan, The Windsors' Hugh Skinner and We Are Lady Parts' Anjana Vasan are among the cast to have joined Olivia Colman and Jessie Buckley in Jonny Sweet's film screenwriting debut, Wicked Little Letters.

As British Comedy Guide reported last week, production on the period comedy-drama, which is based on a true story and sees Colman and Buckley's characters playing very different neighbours who unite to solve a poison pen mystery, is underway in Sussex.

Malachi Kirby, Gemma Jones, Eileen Atkins and Alisha Weir have also joined the cast.

Thea Sharrock directs the story, in which Peep Show star Colman plays pious Edith Swan, who has little in common with fiery Rose Gooding (Fargo's Buckley), aside from them being neighbours in the seaside town of Littlehampton in the 1920s.

One day, Edith and others in the town start receiving scandalous letters written with foul language as eccentric as it is obscene, and the finger of suspicion immediately falls on Rose. As Rose stands to lose her freedom and the custody of her daughter, and outrageous letters continue to blight the town, police officer Gladys Moss begins to suspect something is amiss. Together with a group of resourceful women, Gladys endeavours to solve the mystery, liberate Rose, and catch the real culprit.

Wicked Little Letters is being produced by STUDIOCANAL (Johnny English, Paddington), Film4 (The Full Monty, The Inbetweeners), Blueprint (The Banshees Of Inisherin, The Best Exotic Marigold Hotel) and Colman's South Of The River Pictures (Landscapers).