Katherine Jakeways Creator, Executive Producer Kristine Froseth Nan St. George Actor Alisha Boe Conchita Closson Actor Josie Totah Mabel Elmsworth Actor Aubri Ibrag Lizzy Elmsworth Actor Imogen Waterhouse Jinny St. George Actor Mia Threapleton Honoria Marable Actor Christina Hendricks Mrs. St. George Actor Josh Dylan Lord Richard Marable Actor Guy Remmers Theo, Duke of Tintagel Actor Matthew Broome Guy Thwarte Actor Barney Fishwick Lord James Seadown Actor Leighton Meester Actor Jacob Ifan Hector Robinson Actor Maria Almeida Actor Greg Wise Reede Robinson Actor Grace Ambrose Paloma Ballardino Actor Amelia Bullmore The Dowager Duchess of Tintagel Actor Michael Jean-Marain Lord Halcrest Actor Susanna White Executive Producer Beth Willis Executive Producer William McGregor Director Edith Wharton Writer Georgia Christou Writer