The British actress, 35, stars in the flick as the female lead, Amy Dunne, the subject of the whodunit murder-mystery tale. An adaptation of Gillian Flynn's best-selling novel of the same name, Gone Girl puts the actress in intense scenes with Affleck, who plays her character's murder-suspect husband, Nick Dunne, and uncomfortable ones with Harris, who plays Amy's ex, Desi Collings.
"Ben and I would have these scenes that were very giggly and sort of romantic, and then we'd go to this very dark place…" Pike says in the cover story of Glamour's October issue. "I tried to get us out of that."
"Neil [Patrick Harris] was incredible at that," she continued. "We were in hysterics in the editing room."
The laughter didn't stop there. Pike admitted that she found humor in her supposedly steamy sex scenes with the How I Met Your Mother alum, 41.
"It was very funny doing [rehearsals for our sex] scene," Pike spilled. "[Director] David [Fincher] left Neil and me alone on that set for like two hours to make sure we could do it. But when it’s just two of you, basically kind of f–king on a bed, it feels so inappropriate."
She continued to find comfort in laughter while filming the thriller, telling Glamour that she used humor to deal with playing her troubled character.
"There were definitely moments when I felt very uneasy with how much power Amy had," Pike said. "And the interesting thing is, my reaction was to laugh, to get sort of uncontrollable giggles. That was the most curious part of playing her: At the point where she's at her most powerful, it unnerved something in me."
The tough role is a major one for Pike, who has been in the industry since the late 1990s. Pregnant with her second child with her boyfriend Robie Uniacke, Pike is staring down probable A-list status with Gone Girl, after decades of taking on smaller roles in less-hyped movies and TV shows.
"The question is really why do so many women’s careers take off just as they have children?" the mother to son Solo, 2, pondered to Glamour. "Is it because you are risking everything in your relationship and the risk-taker in you carries through into your professional life? You have less time to worry and overanalyze — maybe that's it. Or the huntress instinct to provide for your family is awoken. [Either way,] with children you spend so much time reexperiencing the world as a child experiences it, and that has a nourishing effect on your imagination — in my job, imagination is key."
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