Rarely do dresses that are so famous they’re practically celebrities in their own right come along. Monica Lewinsky had one. Michelle Obama had at least three. Kate Middleton will have one when she weds on April 29, but has made another a pretty big deal — and it’s slutty, which (like most celebrities) makes it an even bigger deal. It’s the see-through scrap of a thing she wore in a charity fashion show when she was at St. Andrews — the dress that gave the prince a dance in his pants and started it all. Tomorrow it goes up for auction “alongside hundreds of grander garments,” Robin Givhan writes in the Daily Beast, including rare vintage Chanel and Yves Saint Laurent pieces. But this see-through dress thing — which was originally supposed to be a skirt — is the most hyped in the auction, and is expected to fetch $11,000 to $14,000.