The guests, clockwise from top left, wore Ralph Lauren exclusively: Lord and Lady Spencer, Lady Kitty Spencer, and Andrew Lauren; David Gandy and Mollie King; Chris Peck and Toby Huntington-Whiteley; Lottie Moss; Laura Whitmore; Alice Eve. Bottom left: A warm welcome to the evening. Opposite page: The exterior entrance to Althorp Estate, the storied Spencer family home in Northamptonshire, England.