Being the offspring of one of the most prolific figures in fashion, Tommy Hilfiger, it comes as no surprise that Ally has an impeccable sense of style. The model, socialite, and stylist may be making her millions from swanning around with like-minded Daddy's Girls but she also inherited his style-savvy brain and we can't knock her for that. Ally was flaunting her enviable genes at the opening of a Zac Posen store in New York yesterday afternoon; donning a quirky take on this seasons most sought after style- the 19040s inspired, midi dress. The asymmetric, floaty hemline and luxurious, draping fabric bring vintage glam bang up to Autumn/Winter 2011. Rolled up sleeves, an unbuttoned neckline and on-trend accessories give this retro aesthetic a stylishly bedraggled vibe - providing the outfit with a sense of individuality that is so key this season. Zooey Deschanel, Vera Farmiga and Dita Von Teese have all embraced the midi trend whilst still showcasing their own, unique styles. If you're loving Ally's classy look as much as we are, but aren't sure what design suits you best or how to accessorise your mid-length LBD, then navigate yourself to our editorial where we give you, all the insider knowledge you need to carry off the midi mania. In the meantime if you're got the madness for a midi, cast your eye over these beautiful designs which we'd love to have hanging in our LBD wardrobes...