The lead actress has been chosen to star in the new £8m Mary Poppins musical, which promises to be one of the most lavish shows in the West End.
The 22-year-old has previously appeared in My Fair Lady
Laura Michelle Kelly, from Totton, near Southampton, said she was "absolutely thrilled" to have landed the role in the Sir Cameron Mackintosh production.
The 22-year-old has previously made her mark in the West End, by following in the footsteps of Martine McCutcheon to play Eliza Doolittle in the last six-month run of My Fair Lady.
She has also appeared in Les Miserables, Mamma Mia, Beauty and the Beast and
Whistle Down The Wind and is currently appearing in Fiddler on the Roof on Broadway.
The opening of the production will coincide with the 40th anniversary of the Disney movie classic starring Julie Andrews and Dick Van Dyke.
It has been written by Oscar-winning screenwriter Julian Fellowes and includes many of the original songs.
Brink of stardom
Kelly said: "I am absolutely thrilled at the opportunity I have been given.
"This is truly the role of a lifetime."
Sir Cameron said: "When we started discussing the casting of Mary Poppins for the stage, we dreamt of finding an actress who was on the brink of stardom, but not yet associated by the public with a particular role.
"We are thrilled that Laura has won the part and we feel sure she will bring
her own unique quality to this extraordinary and much-loved role."
The musical will open in the West End at the Prince Edward Theatre on 15 December, after an eight-week run at the Bristol Hippodrome.