Rachel Brosnahan is set to star in 'The Switch'.

The 29-year-old actress will play the lead role in the movie, based on a novel of the same name by Beth O'Leary.

The plot focuses on a Leena, 29-year-old woman and her 79-year-old grandmother, Eileen, who decide to swap lives.

Leena moves into a village in Yorkshire and takes on dog walking, whilst Eileen finds herself in a London flat and navigating the world of dating apps.

Amblin Partners have acquire the rights to the movie, which will be adapted for the big screen by Bakka Bowling.

Kristie Macosko Krieger will produced, with Rachel and Beth serving as executive producers. Jeb Brody will oversee the project for the studio.

Rachel revealed that she was ''deeply moved'' when she read the story.

In a statement, 'The Marvelous Mrs. Maisel' star said: ''I am thrilled to be partnering with Amblin to bring Beth O'Leary's beautiful book to life.

''I was utterly charmed and deeply moved from the first page to the last and can't wait to share Leena and Eileen's story with everyone.''

Beth added: ''I couldn't be happier that 'The Switch' has found a home with Amblin. I came away from my first call with Kristie, Jeb and the team absolutely buzzing - their vision for The Switch is just so exciting.

''I'm a huge fan of Rachel, too, so it's an absolute dream to have her both starring and exec producing. Basically, I'm still pinching myself.''

Kristie added that Rachel is ''a force to be reckoned with'' as a performer.

She said: ''Beth has written a gorgeous, sweet and funny book in The Switch, and I couldn't be more excited to start this journey with her.

''As we all know by now, Rachel is an amazing actress and a force to be reckoned with - I'm delighted she's agreed to come on board as both an actor and executive producer.''