We were pretty enthralled by HBO's 'The Staircase' already, but now we're whole-heartedly invested that the series will deliver (no pressure).

Sophie Turner is lined up to join 'The Staircase', HBO Max's dramatisation series on the plot-twisting real-life happenings of the Peterson household. HBO's 'The Staircase' will be based on the Netflix series of the same name, which followed the complicated court case of Michael Peterson, and the heavy toll it took on him and his family following the mysterious death of his wife, Kathleen.

Sophie will join the previously announced Colin Firth as Michael Peterson, Toni Collette as Kathleen Peterson, and other cast members which include Juliette Binoche ('Chocolat'), Rosemarie DeWitt ('Your Sister's Keeper') and Parker Posey ('Dazed and Confused').

Sophie Turner will play Margaret Ratliff, who is one of Michael Peterson’s adopted daughters. As we saw in Netflix's 13-episode docuseries, Margaret is the daughter of Elizabeth Ratliffe, who also died under inexplicable (and somewhat similar circumstances to Kathleen) in Germany. She was the neighbour of Michael and Kathleen at the time, and the couple adopted her two daughters, Margaret and Martha.

The director of the eight-episode limited series will be Antonio Campos ('The Devil All the Time'). Maggie Cohn ('American Crime Story') co-wrote the series with Antonio. 

Sophie Turner recently took a short break from acting to start a family with her husband Joe Jones. Last year, the couple welcomed their baby girl Willa. The actor starred as Sansa Stark in 'Game of Thrones' for eight seasons and also played Jean Grey in Fox's most recent iteration of The X-Men. Last year she starred in streaming platform Quibi's TV series 'Survive'.