Iconic French chanteuse Juliette Greco joined Katy Perry, Leigh Lezark, Elettra Wiedemann and actress Sylvie Testud to clap and cheer the dancing models at the disco-themed Sonia Rykiel show Sunday night. Greco said she’s preparing to tour Japan, where she has a loyal following of fans, before returning to France for a one-night concert in Versailles in December.