Julie Andrews is "100 per cent behind" 'Mary Poppins Returns' - but won't appear in it.

Julie Andrews

Julie Andrews

The 81-year-old actress - who played the magical nanny in the 1964 musical fantasy film - is backing the forthcoming project and is pleased director Rob Marshall has chosen Emily Blunt to portray the leading role because she thinks she's "amazing."

Speaking to Entertainment Weekly, Marshall said: "Julie was incredibly gracious. We talked about it in a very general way but she made it clear right up front.

"She said, 'This is Emily's show, and I really want it to be Emily's show. I don't want it to be, "Oh, here comes that Mary Poppins. I don't want that." I really want her to take this and run with it, because she will be brilliant.'

"Julie will always be, for me and for everybody, the most astonishing performance as Mary Poppins, winning the Oscar and bursting onto the scene so brilliantly. But Emily is the perfect person to carry the torch, and I know Julie feels the exact same way."

Although Julie has turned down the chance to make an appearance in the film, Dick Van Dyke - who played jack-of-all-trades Bert in the original - will make a cameo.

Details of the plot are under wraps at the moment but it is known that Mary will re-visit the Banks family after a family tragedy.

The news that 'Mary Poppins Returns' was in development by Disney broke in 2015 and it was reported that the film would feature a standalone narrative based on the remaining seven books in the series.

The movie will also star Ben Whishaw as a grown-up Michael Banks, Emily Mortimer as Jane Banks, Angela Lansbury as the Balloon Lady and Julie Walters as Ellen.

Shooting on the film started on February 10, at Shepperton Studios in Surrey, England.