In the September issue of Vanity Fair, Jessica Chastain’s sultry, topless photo shoot exudes glamour, poise and confidence. But under the surface, the Oscar nominee is “really, really terrified.” Chastain, who is preparing to make her Broadway debut as Catherine Sloper in the highly anticipated revival of The Heiress, doesn’t see herself as a dazzling starlet on the rise. “I’m the unknown everyone’s already sick of,” she told Vanity Fair. After starring in six movies in the past year, including The Tree of Life, The Help, Lawless and Wilde Salome, Chastain downplays her success. “I haven’t been this unsure in a long time, ” she said of her forthcoming turn in The Heiress. “I have a feeling that very soon I’m going to fail very, very big.” (Not to worry, Jessica: You've got Moises Kaufman as your director!) Check out Chastain’s sexy photo spread by Mario Testino, then see her tackle The Heiress on Broadway opposite Downton Abbey's Dan Stevens and David Strathairn, beginning October 7.