Casting director Victoria Thomas on booking Mikey Madison, Austin Butler, Margaret Qualley, and Sydney Sweeney just before their careers took off. Photo-Illustration: Vulture; Photos: Columbia Pictures When Quentin Tarantino’s Once Upon a Time in Hollywood opened in the summer of 2019, the prerelease hype centered on the film’s star power. It would be the first-ever onscreen team-up of Leonardo DiCaprio and Brad Pitt , with Margot Robbie adding her own considerable wattage. While both of the