Gone GIrl
Credit: Youtube

Finally! Gone Girl opens tonight—are you pumped? You should be. And not just because the thriller is packed with talent you’ll love watching on screen (ahem, Ben Affleck, Rosamund Pike and Neil Patrick Harris). Behind the scenes features just as many Hollywood heavy hitters, including the gifted costume designer Trish Summerville, who has worked her magic on other badass films such as The Girl with the Dragon Tattoo and The Hunger Games: Catching Fire.

In this project, Summerville re-teams with her Dragon Tattoo director David Fincher to bring Gillian Flynn's wildly successful book of the same name to the big screen. InStyle caught up with to get all the inside deets about turning Amy and Nick Dunne into a reality. “I had read Gillian’s book and loved it,” she told us. “And I knew David Fincher would bring his touch to it that would make it even more interesting and a bit more twisted.” Read more of her inside scoop below.

1. Because so many millions read the book, her job became a little more tricky.“Everybody has an idea of what the clothes should be, especially because it is set in a contemporary time,” Summerville explained. “But we just felt it had to be really real and really authentic. We wanted you to be able to identify with Amy and Nick—that they could be the people that live next door to you, and there was nothing that really stood out about them that would make them too odd or too strange.” Therefore, she kept looking for simple clothing. “I wanted things that looked like everyday life, like the people who shop at the mall and order things online,” she said. “So in that sense, it was a challenge to figure out what their everyday life is really like.”

Credit: YouTube

2. For Amy’s character, she had to keep her looking like the “cool girl.”“There was levels of trying to keep her traditional chic but the everyday girl,” she says. “It’s a thing we always had to keep in mind: The cool girl. That meant relying upon more of simple classic pieces rather than being overwhelmed by fashion and clothing. She’s just kind of not that girl.”

3. Ben Affleck had to get most of his looks tailored.“He’s a really big guy, and he’s very broad in the shoulders,” says Summerville. “He kind of has a swimmer’s body, where he’s small and slender in the waist. So the key with him is a lot of tailoring on his pieces.” And when he did have to put on some suits, she felt the designer duds fit him best. “We did a lot of Dolce & Gabbana suits for him and Prada shirts worked really well too,” she said. “Those have a nice fit with stretch.”

4. It was pivotal to get Nick Dunne’s blue shirt just right.When Nick Dunne comes home to find wife Amy gone, little did he know the shirt he threw on earlier that morning would be one he’d stay in for several days. So when it came time to sourcing just-the-right button-up for Ben Affleck’s character, Summerville chose a blue design by Steven Alan, which she paired with comfy J Brand jeans. “Most men are typically drawn to blue,” she explained of her choice. “It became a joke with [director David] Fincher and I because we had so many blue shirts for him. This one fit him really well, and it’s really, really soft.” It also kept him cool: “We shooting in the dead heat in Missouri, and this was really lightweight.”

5. Amy’s key jewelry pieces are meant to be meaningful keepsakes.Look closely as you watch and you’ll notice Amy wearing a rose gold Cartier Love bracelet. “She keeps it through everything because that’s her signature kind of piece,” says Summerville. “I felt it fit very well for Amy because it’s timeless and it’s classic.” You’ll also spot a floating ‘A’ on a necklace. “I felt like certain parts of Amy have remained the same since high school through college, and this would be one of those keepsakes she has forever.”

6. Amy tries to fit into her Missouri life by wearing more muted colors.Summerville (above) made subtle changes in Amy’s costumes to signify a change, transitioning Amy from a big city New York look to a subtler Missouri suburbanite. “She introduces some soft colors in her palette, she’s wearing jeans more, maybe not heels all the time,” explains the costume designer. “It’s just trying to make those subtle transitions that make her this real-life person that you could go have coffee with and you don’t realize what’s really conjuring up in the house.”