Carey Mulligan has joined Bradley Cooper's biopic about Leonard Bernstein.

The 45-year-old actor is set to star in and direct the upcoming movie, 'Maestro', which follows the life of the legendary conductor and musical maestro behind 'West Side Story' and 'Candide'.

And now he's confirmed the 'Promising Young Woman' star has been cast as Bernstein's wife Felicia Montealegre.

Bradley told Deadline: ''I was struck by Carey ever since I saw her on stage many years ago and I haven't missed a performance of hers since.

''I am humbled to be working with such a mammoth talent, as well as such a kind person in Carey.''

The film - which will debut on Netflix - spans over 30 years, telling the story of the complicated marriage between the pair.

They had three children together, but Felicia knew about Leonard's affairs with other men before and after their wedding.

The children have given their seal of approval of Carey, 35, portraying their mother.

Jamie Bernstein said: ''We're absolutely thrilled that Carey Mulligan will play our mother in 'Maestro'.

''Carey will surely capture Felicia's unique combination of wit, warmth, elegant beauty, and depth of emotion. We also love the way Carey conveys a kind of storybook European grace, which was something our mother embodied as well.''

The script has been penned by Bradley, with the help of Josh Singer, who previously helped to pen 'Spotlight'.

The 'A Star Is Born' helmer earned the rights from the Bernstein Estate and has been working closely with his children, Jamie, Alexander and Nina for the past two years.

Previously, it was also confirmed that Jake Gyllenhaal was also set to star in another movie about the late composer titled 'The American', which would have been helmed by Cary Fukunaga.

However, plans for the movie were eventually scrapped amid concerns Leonard's name wouldn't draw a big enough audience.