The actress suggested that Looper's time-bending plot about an assassin trying to change his past carries an underlying message about family.
"I think the film Looper is about redemption and I think it's about the redeeming qualities of love," Blunt said, reports Flicks and Bits. "And also how nurture can alter natures path in some ways. And I guess the question is nurture versus nature, and how much are we programmed genetically and how much are we programmed by how people treat us?"
She added: "It's so rich in complexity, and conceptually it's so exciting, but also emotionally it is too."
Blunt went on to reveal that she wanted to sign on for Looper after reading just a small section of the script.
"When I first got the script for Looper, I read about 30 or so pages and I was already on the phone to my agent," she recalled.
"I hadn't even gotten to my character and I was like, 'Get me this movie'! Because I loved it so much!"
Looper's Joseph Gordon-Levitt recently said it was important to study Bruce Willis in order to play a younger version of Willis's character.
The film is now playing in the US and the UK. Watch a trailer below: