bridesmaid dresses designers Elegant Grey Blue A-Line Dress with Flutter Sleeve - Blue Designer Bridesmaids with V-Neck - Multiple Color full Chiffon skirt and Designer Bridesmaid Dresses & Gowns

If you can get your hands on a good substantial bumpad, you could probably get away with making this dress work for Marie Antoinette/Enlightenment/1780's, but again accessories and hairstyle/millenery will be crucial, as the colors are a bit more Victorian

Plus, to help you get Middleton's full look, I added in a few gorgeous blue dresses below too

2-in-1 tweed-effect short dress Fitted rib knit top Structured tweed skirt and jacket Removable white collar Round gold buttons White scalloped trim on the hem and sleeves The spirit of Parisian hotel 2-in-1 tweed-effect short dress Fitted rib knit top Structured tweed skirt and jacket Removable white collar Round gold buttons White scalloped trim on the hem and sleeves The spirit of Parisian hotels is expressed through an interplay of textures and graphic contrasts, revealing the modern, assertive femininity that is the signature of the Maje woman

A good tip is to check your local Blue Martinis event calendar for dress code specifics for that night