“I never thought I’d get the part in the film, whatever it was,” says Tuppence Middleton, 33, the actress who stars alongside Gary Oldman in Mank, David Fincher’s ode to Orson Welles and the golden days of Hollywood. After originally auditioning for the role of Herman Mankiewicz’s secretary, which went to Lily Collins, Middleton stepped into the role of Sara—the protagonist’s aggrieved wife, who earns the nickname “Poor Sara.”

Written by Fincher’s late father, Jack Fincher, Mank charts the creative tug-of-war between screenwriter Mankiewicz and Welles. Of Fincher, Middleton explains, “He was one of those directors who’s on my top five of, you know, favorite directors of all time to work with. So it’s kind of like that ‘pinch me’ feeling where you think, I’m sure that won’t happen to me.”