Emily Blunt became "Mary Pump-ins" as she played Disney's beloved magical nanny just six weeks after giving birth to baby Violet.

The 35-year-old actress' turn as Mary Poppins in the much-anticipated sequel to the hit 1964 Julie Andrews film opens on 19 December (18), and while promoting the movie, Emily recalls dashing off to pump breast milk in between takes.

"(I was) Mary Pump-ins; that’s what I felt like," she tells Vogue. "It was ridiculous."

But she felt she couldn't ask for more time off after asking director Rob Marshall to push back rehearsals because of her pregnancy: "I said, 'You’ve got to give me four or five months before I’m ready to crack on with the rehearsals, for the baby."

The downtime proved invaluable as it allowed Emily the chance to really "become" Poppins and create her own version of the character made famous by Andrews over half a century ago.

And she was also glad to be singing some upbeat songs after playing a tortured, alcoholic ex in The Girl on the Train.

"It was medicinal, singing these happy Mary Poppins songs after what I'd been through every day," she tells the publication.

"Poor Violet, she’d been rattling around inside me while I played this alcoholic train wreck. But then I think she benefited from all the singing."

A month and a half after welcoming Violet, Blunt was on the set, "ducking out every so often to pump milk".

She's convinced all the effort was worth it as Marshall has created a beautiful film in Mary Poppins Returns - and everyone needs a little Poppins in their lives right now.

"You could say she’s some sort of angel," Emily explains. "She recognises what people need, and she gives it to them, yet they discover something about themselves in the process."