The Girl On The Train, which has sold over three million copies in the US alone, made publishing history when it claimed the number one spot of the UK hardback fiction charts for 20 weeks in a row - the longest any book has ever held the top spot.
So, when Universal announced plans to adapt the book into a movie, fans were eager to know which actress would take on the role of Rachel Watson.
Cue Emily Blunt stepping into the shoes of the book’s unreliable narrator – and wowing audiences in the film’s first gripping trailer, which sets up the moment Rachel sees something truly shocking from a train window.
But, speaking with Entertainment Weekly, the actress admitted that she wasn’t drawn to the role because of the book’s popularity.
Instead, it was down to the fact that it’s so rare for a damaged, frightening, or messed-up woman to be the star of the film – after all, Hollywood is usually filled with ‘perfect’ female characters.
“I was completely sucked into it and thrilled by the idea that your protagonist was a blackout drunk,” said Blunt.
“That’s very unusual. Especially in cinema, to have a woman who’s just so messed-up at the forefront of the film.”
Read more: watch Emily Blunt lose her mind in the ominous Girl On The Train trailer
The Devil Wears Prada star went on to explain that she also loves the fact that the prominent cast and crew positions on The Girl On The Train are filled with women; Rebecca Ferguson and Haley Bennett are her co-stars, Charlotte Bruus Christensen is the cinematographer, and Erin Cressida Wilson penned the script.
However Blunt added that she understands many people may be surprised to hear that she gets along so well with her female colleagues – particularly as it goes against sexist stereotypes in the media.
She explained: “We were all talking one day, and Charlize [Theron] was like, 'Do you know what's funny is I think sometimes, whether it's the media or just society, [people] like to paint the picture that women sort of bitch about each other, and women are competitive and jealous and vying and watchful of each other.
“And she said, 'And you know, the only issues I've ever had on set have been with a dude.' And I would agree. The only time I feel like I've rolled my eyes at somebody I've been working with, it's been a guy.”
Read more: Emily Blunt reveals dark truth about Disney's Mary Poppins Returns
Blunt added: “It's just been my experience that I've gotten along with every woman that I've worked with. I have not felt any preciousness or hierarchy or anything like that. I've just never had an issue!”
Due to the hand-held style of filming used for The Girl On The Train, Blunt actually found herself forging a strong bond with Christensen, explaining that it takes a great deal of trust to expose your rawest emotions when there’s a camera so close to your face.
“[It was like] doing a dance,” she said.
Read more: Emily Blunt has her say on the gender pay gap
While The Girl On The Train is not scheduled to hit cinemas until later this autumn, Blunt’s husband, John Krasinski, has already seen the movie in full.
And, speaking to Popsugar, he insisted that it’s “the best she’s ever done”.
He said: “I can say genuinely for the first time, it's the only time since, as long as I've known her, that I ever forgot that it was her on screen. That's how good she is in this movie, which is very rare and very hard to do.
“She goes so full into the transformation of someone who's going through obviously a struggle in her life and a struggle with addiction, and it's just incredible.”
Krasinski added: “She's so good. She's always so good, but this is like a tour-de-force performance for me.”
The Girl On The Train will arrive in cinemas on 7 October 2017.