I can't believe it's not Erdem....

This is the best High Street version of the Erdem dress (as worn by Michelle Williams) I have seen so far...

It's a gorgeous raspberry red colour with intricate lace detail and beige underlay. It also comes in a turquoise colour and electric blue and is available in French Connection.

Credit: Zimbio Pictures

Check out: http://www.frenchconnection.com/product/Woman+Collections+Dresses/71XI5/Anna+Lace+Dress.htm