In Gone Girl, director David Fincher’s adaptation of the smash word-of-mouth bestseller, British actress Rosamund Pike portrays the titular vanished character as a kind of bewitching cypher.

As detailed in an exclusive Entertainment Weekly cover story available on newsstands now, Amy is a Big Apple sophisticate with a Harvard degree who moves to small-town Missouri with her husband Nick (Ben Affleck), assiduously chronicling her bend-over-backward homemaking attempts, increasingly loveless marriage, and spouse’s rage issues in a diary. So when Amy vanishes in a flourish of broken glass and mysterious arterial spray on the couple’s fifth wedding anniversary, Nick becomes the investigation’s prime suspect. But in the absence of a corpse, it’s uncertain whether Amy is dead or just… gone.

Although Pike (Jack Reacher, The World’s End, An Education) is relatively well-known in her native England, she’s hardly a household name in the U.S. Consequently, American audiences will likely have no preconceived notions of what she may or may not be capable of. And for now, Pike prefers to keep it that way.

She acknowledges, however, that she prepared for the role by reading “true crime books” and watching YouTube videos chronicling certain murdered, and murderous, young women whose soap-operatic journeys captivated the public imagination: Laci Peterson and Jodi Arias.

Moreover, Pike modeled Amy, at least in part, on Carolyn Bessette-Kennedy, the alluring but somehow unknowable wife of John F. Kennedy Jr., both of whom died in a plane crash in 1999.

“There’s not much out there about her. You never heard her speak,” Pike says, curled up on a sofa at Milk Studios in Hollywood, showing the contours of a baby bump—her second child with her longtime partner Robie Uniacke. “You just see those pictures of her hiding her face. The way she moved—I used quite a lot of that body language and mood.”

“She’s the dream girl,” Pike continues. “That’s what Amy was for Nick. She’s the one you can’t get out of your head because she’s perfect.”