Leave it to the fashion set to make turning 90 something stylish. As London Fashion Week heats up, the site of the most sizzling party was Claridge’s, where Joan Burstein—the legendary retailer affectionately known as Mrs. B—was the toast of the town celebrating her birthday. Taking in the festivities were Anna Wintour, John Galliano, Alber Elbaz, and countless others who started the evening with a champagne reception. Joining in the fun later on were Manolo Blahnik, Nicole Farhi, and Sir Philip Green, who also took in a sumptuous three-course menu as the soundtrack of Frank Sinatra and Nina Simone brought everyone to a bygone era.