Charles James is the subject of this year’s big exhibition at the Costume Institute of the Metropolitan Museum of Art. Given that James, the midcentury American couturier, was best known for his ultra-soigne, engineered ballgowns, we can expect the VIPs on the Met Gala’s red carpet to opt for looks super-dramatic and extra polished. Mr. Valentino made a 45-year career designing exactly those kinds of elegant knockout frocks—and the Met Gala has frequently been a showcase for designs from his archives. Last year, for instance, one of the looks topping watchers’ “Best of the Met” lists was Anne Hathaway’s sheer-paneled black gown with feathered sleeves—a Valentino couture look from 1992. In 2011, Natalia Vodianova also went for a black and feathered number, albeit of a more recent vintage: Her Valentino couture dated from 2007. And in 2007, Jennifer Garner did her own dig through the archive, and turned up a stunning, bustiert-topped column dress in Valentino-signature red. The coup de grace? The vast train, which spread like a peacock tail. All these ladies came to the Gala with the chic-est accessory, too: Mr. Valentino himself, natch.