Despite being largely identified for playing Mary Poppins and winning an Oscar for it in the 1960s, Julie Andrews did not want to be in the reboot, "Mary Poppins Returns." The upcoming Disney movie, whose story has been updated from the original, has cast Emily Blunt in the iconic leading role, and there's a big reason why Julie Andrews said no to even a cameo.

"Mary Poppins Returns" director Rob Marshall spoke to Julie Andrews about doing the reboot and she expressed excitement when she learned Emily Blunt snagged the part. But when asked if she would make a special appearance like her former co-star Dick Van Dyke, who agreed to a cameo, the actress refused upfront.

Emily's show

"This is Emily’s show, and I really want it to be Emily’s show," Julie Andrews reportedly told the director, according to Entertainment Weekly. "I really want her to take this and run with it because she will be brilliant," she said.

In preparing for the role, Emily Blunt said she thought of watching the original movie first, but realized she needed to bring something original and not simply copy what Julie Andrews did. So, she turned to the books to learn about her character, which helped the actress develop a style in terms of how to play the magical nanny.

Twenty-five years after 'Mary Poppins'

"Mary Poppins Returns" will pick up 25 years after the events of the original film.

Her ward Jane (Emily Mortimer) and Michael (Ben Whishaw) have grown up and are raising their own kids. Emily Blunt's Mary Poppins comes back to town to help Jane and Michael with their kids as they struggle with a life-changing event.

It's unclear what Dick Van Dyke will play in "Mary Poppins Returns" but he won't be reprising his role as Bert, the street artist, and Mary's friend.

In his place, Lin-Manuel Miranda will take on the role of Jack, the street lamp cleaner. "The magical is commonplace, at least to a couple of people like Mary and Jack, similar to the way it was to Mary and Bert," Miranda said in an interview.

Joining Emily Blunt and Lin-Manuel Miranda are Meryl Streep (Topsy), Colin Firth (William Weatherall Wilkins), Angela Lansbury (the Balloon Lady), Julie Walters (Ellen) and Jeremy Swift (Gooding).

The film has a scheduled release date of Dec. 25, 2018.

Mary Poppins was created by P.L. Travers in a series of books. In 2013, her life story was turned into a movie, "Saving Mr. Banks.” It depicted how Disney worked with P.L. Travers, who was played by Emma Thompson, to deliver her story to the big screen. Tom Hanks played Walt Disney in “Saving Mr. Banks.”