Benedict Cumberbatch (Patrick Melrose) & Margo Stilley (Cindy Smith) also worked together on Murder Is Easy (2008) as Luke Fitzwilliam & Bridget Conway respectively.
Harriet Walter joins the ranks of the likes of Lucy Cohu in The Queen's Sister (2005), Katie McGrath in The Queen (2009), Ramona Marquez in The King's Speech (2010), Bel Powley in A Royal Night Out (2015) and Vanessa Kirby and Helena Bonham Carter, (both in The Crown (2016), in portraying Princess Margaret.