Sexy Solid Backless Slit Strapless Irregular Dress Dresses Diana Slit O Neck Backless Midi Dress Diana Sleeveless Structured Midi Dress In Off White Alice + Olivia Why must every dress be backless? The Spinoff. Features: This Diana Slit O Neck Backless Midi Dress is perfect for a night club party. It features an elegant tight fit with a fashionable lantern sleeve and a sexy slit o neck backless design. It's a chic and fashionable way to show off your style.