If there's one person whose hair we're always paying attention to, it's Kate Middleton. The Princess of Wales is famous for her impossibly glossy blowouts - the kind of shiny, satin-like hair that somehow looks perfect at every royal appearance. Naturally, we had to know the secret. Turns out, her go-to shampoo isn't some impossible-to-find luxury formula. According to Kate's Closet, Middleton washes her hair with Kérastase Nutritive Bain Satin Riche Shampoo, a nourishing French formula designed to leave strands smooth, soft and incredibly shiny.