The British actress will reprise her role of ambitious Emily Charlton in the sequel to the 2006 smash hit about a fictional fashion magazine, starring Meryl Streep as its terrifying editor and Anne Hathaway as her assistant.
The sequel, which is currently filming, is eagerly anticipated and fans and photographers have mobbed the set when the cast are shooting on the streets of New York.
Blunt, who was nominated for an Oscar for her turn in Oppenheimer, said one of the downsides of returning to the world of high fashion is the uncomfortable footwear.
She told Porter magazine: "I don't love wearing heels, so getting back to The Devil Wears Prada has been a rude awakening for all of us."
Asked what he has been like to revisit the role, she replied: "Wild. I'll say that."
She added: "When we made the first movie, none of us expected the meteoric life that it would have and the impact it would have on people.
"As my husband (actor and director John Krasinski) said to me the other day, this is people's nostalgia bank. They've watched this with their families 50, 60 times; they've watched it when their parents are sick; they've watched it when they're sad, when they've gone through a break-up.
"Of course, I meet people who will quote the movie to me, but I'm not sure I've ever been hit with a bombardment of the realisation of what the movie is to people coming back to the film set. And that's what we all feel, holy cow. That's what everyone says, every day: holy shit."
While the film gave Blunt one of her most indelible roles, it also gave her a new family member - her co-star Stanley Tucci went on to marry her sister Felicity.
She said: "It has deep emotional roots for a lot of us," Blunt says simply.
"It's not just doing a movie."
She added of Tucci: "He's not good for your Devil Wears Prada diet though, because he's cooking pasta and making me drink martinis with him every night.
"He was like: 'Em, do you want some pomodoro pasta?' I'm like: 'I do, but I have to be in Dior couture today, so we'll see.'"
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