By InStyle Staff
Oct 06, 2016 @ 7:00 am

Perhaps what makes Emily Blunt so mesmerizing as the alcoholic lead in the film adaptation of the best-selling novel, The Girl on the Train, is that the character couldn’t be further from her real-life disposition. Each day on set, the 33-year-old actress transformed from a beloved, quick-witted new mom to an isolated, blackout drunk—and managed to do it so believably that the film’s cinematographer calls her an Oscar contender.

“This was a very challenging role in more ways than one, very far removed from who I am as a person, and so I needed to understand that mindset and the addictive mentality and what it is to suffer with this illness,” InStyle’s November 2016 cover star says in the video above.

“It’s something that I just don’t understand, I’ve never experienced. And so I spoke to people, I read books, and I watched Intervention on a loop, which was really eye opening,” Blunt says. The transformation wasn’t all mental: The mom-of-two spent many hours in the makeup chair to achieve the look of a spiraling alcoholic loosing her grip on reality.

“They gave me sort of a rosacea effect. This was all makeup, a lot of really attractive sort of grey bags and brown lines, just bringing out my own natural lines,” she says. “I wore a full bloodshot contact lens and I had different stages of drunkenness. So some were pinker and some were really red, and they had a yellow one for the hangover. All day I’d have this lovely guy Zach putting drops in my eyes because I was just in agony with these things.” Beauty is pain has never been taken quite so literally.

Blunt walked a fine line between acting unlikeable and untrustworthy, and still playing the audience’s most reliable eyes and ears. “There’s nothing really likeable about her and the way she lives her life, so I saw that as a challenge, you know, that I had to really still pull the audience in,” she told InStyle. “It was an eye-opener, I think, to wear that skin for a while.”

Watch Blunt dish about her much-anticipated new film in the video at top. For more of our Emily Blunt cover story, pick up the November issue of InStyle, available on newsstands and for digital download on Friday, Oct. 14.