Will Anna Wintour wear a zany Schiaparelli chapeau and Prada cat-eyed shades? Will Amazon founder Jeff Bezos, one of the evening’s honorary chairs, spread his infectious laugh from one end of the red carpet to the other? Will attendees be forced to swap their bejeweled clutches for shiny new Kindles? Who will stumble in their Prada racecar shoes? Find out for yourself this evening as the Metropolitan Museum of Art webcasts the arrivals to the Costume Institute Benefit that celebrates “Schiaparelli and Prada: Impossible Conversations.” The livestreaming fun begins here at 6:30 p.m., when Vogue-approved hosts Billy Norwich and Elettra Wiedemann will chat up gala co-chairs including Wintour, Carey Mulligan, and Miuccia Prada, along with whoever else swans past them in a sufficiently whimsical and/or impossible ensemble. Special pre-taped segments will offer a sneak peek at the exhibition, which opens to the public on Thursday, as well as the history of the gala benefit. Look hard and you might just spy Pentagram’s Abbott Miller, who designed the exquisite catalogue.