LOS ANGELES-Emma Watson has joined the cast of 'Little Women'.

The 'Harry Potter' actress will star alongside the likes of Meryl Streep, Laura Dern and Saoirse Ronan in Greta Gerwig's adaptation of Louisa May Alcott's classic novel, replacing Emma Stone, who was unable to commit to the project because of her promotional obligations to 'The Favourite'.

According to Variety, roles in the film are still being worked out so it is unknown which of the March sisters will be played by Emma.

The movie - which is also being written by Greta - tells the story of four sisters as they transition from childhood to womanhood and will also feature Florence Pugh and Timothee Chalamet.

The novel has been adapted for the big screen several time before, including the 1994 version directed by Gillian Armstrong.

That movie featured Winona Ryder as the main character, Josephine 'Jo' March, an ambitious young woman, who longs to become a successful author.

The all-star cast also included Gabriel Byrne, Kirsten Dunst, Claire Danes, Christian Bale and Susan Sarandon.

The upcoming Gerwig-directed adaptation would be a reunion for Gerwig, Ronan and Chalamet, after Greta directed the pair in her directorial debut 'Lady Bird'.

And Saoirse recently revealed that she continues to be mentored by her idol Greta. She said: ''I was a huge fan of Greta Gerwig before I worked with her on 'Lady Bird'.

''Meeting Greta and knowing that she knew who I was and wanted to talk to me about the script was so exciting. We Skyped before we met and we were so giggly, like two kids in high school. She's been very supportive since.

''She's everything I want to be as an actor and as a filmmaker. I could feel myself going from being like, 'Maybe one day I'll direct, to looking at Greta and going, 'I really want to do this.' ''