The Story Behind Keira Knightley's Emerald Green Slip Dress From 'Atonement' British Vogue The green dress Keira Knightley wore in Atonement is my Roman Empire. Ever since I saw this movie Ive dreamed of having a dress just like it. And now I can finally live my #KieraKnightley fantasy. The green dress Kiera Knightley wore in Atonement is my Roman Empire.My life and the lives of countless millennial girls changed when I watched Atonement and saw THE Green Dress for the first time. I Pre Sell Keira Knightley as Cecilia Green Dress Atonement LausenCrafts Keira Knightley Atonement Dress Etsy