Several starlets showed up in dresses cut like cocktail dresses in the front to expose lots of leg, but long in the back to be ball-gown appropriate.
Kristen Stewart did a variation on the look in Chanel Haute Couture, with a sheer panel in the front. Stella McCartney dressed Liv Tyler and herself in the half-and-half dresses. And Sienna Miller wore a spangly Pucci dress in deep blue.
It's sort of a cool idea in theory. But in reality, the neither-here-nor-there look can come off a little like a man's formal tail-coat reshaped for a woman. We don't recommend it for anyone but super leggy stars attending events that focus on making a fashion statement.