AtonementExtraordinary Style cocolaroux The Story Behind Keira Knightley's Emerald Green Slip Dress From 'Atonement' British Vogue Halter tie neck backless gown ivory 4 Sleeveless A line and Open Back Bow Kleinfeld Bridal Keira Knightley Green Evening Dress in Atonement Xdressy Anyone else still thinking about Keira Knightley's backless green dress from Atonement, 13 years later? At the link in bio, our style editor examines why the backless trend became an unlikely