It’s Saturday night during New York Fashion Week, and an abandoned bank on Wall Street has been staged to look like the most sublime 1920s nightclub you’ve ever seen. A jazz band plays. Waiters in white suits serve champagne and martinis. The room is abuzz.

Anna Wintour sits next to Cate Blanchett, while fashion It-girls Eva Chen and Lauren Santo Domingo chat with British Vogue editor Edward Enninful. Janelle Monáe, the evening’s star performer, sashays and preens and struts, singing jazz standards, picking up revellers’ champagne coupes and smashing them to the ground, sending a frisson through the crowd.