Keira Knightley Green Evening Dress in Atonement Xdressy Blakely Bow Back Mini Dress with Train 2X 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 A dress so iconic the original went missing! Keira Knightley's emerald silk gown in Atonement wasn't just the green dress it was the moment. Custom dyed, cut on the bias, and