Brie Larson
Credit: Photographed By: Horst Diekgerdes Styled By: Melissa Rubini

If you're going to see Trainwreck (in theaters Friday), get ready for a lot of laughs, but also a lot of heart. Yes, the rom-com revolves around Amy (Amy Schumer), a bawdy men's magazine editor, and her mostly dysfunctional relationship with Aaron (Bill Hader), a sports doctor. But its the scenes between Amy and her younger sister Kim (Brie Larson) that might be the most relatable.

While Schumer plays a serial dater that has no intention of ever settling down, Larson's character is already married, pregnant, and much more conventional. "One of the reasons I took the role is because I also have a sister that is the exact opposite of me in every way," says Larson, who is featured in the August issue of InStyle (pictured, below), on newsstands now. "Before Trainwreck, I had never seen a film capture what we are really like. I thought that it was important to watch these girls go in two completely different directions in their lives, yet always find a way back to each other."

Brie Larson BTS
Credit: Lisa Martin

Even though their characters struggle through some family drama on screen, Larson says she had fun with Schumer when the cameras were off, mostly going to comedy clubs around New York. "I had seen Amy's stand up before I met her in person and she blew me away," Larson says. "She is brilliant in everything she does."

And now, thanks to Schumer and the film's director Judd Apatow, Larson has caught the comedy bug, too. "I've always been drawn to dramatic roles, but nothing compares to laughing. It's like a spoon full of sugar," she says.

Check out the Trainwreck trailer below, and for more of our interview with Larson, pick up the August issue of InStyle, available now on newsstands and for digital download.