The actor will team up with Pitt's Plan B production company on the drama after the actor acquired big-screen rights to the Chimamanda Ngozi Adichie-penned novel, said the Hollywood Reporter.
Nyong'o will also produce and star in the movie, which is an epic love story of young Nigerians, spanning continents while exploring the cruelties and the humour of both the modern immigrant experience and the difficulty of finding your way home.
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Adichie is best known for her novels Purple Hibiscus and Half of a Yellow Sun, which was also adapted for the big screen.
"It is such an honor to have the opportunity to bring Ms Adichie's brilliant book to the screen," Nyong'o said.
"Page after page, I was struck by Ifemelu and Obinze's stories, whose experiences as African immigrants are so specific and also so imminently relatable. It is a thrilling challenge to tell a truly international story so full of love, humour and heart," said the actor.
Nyong'o made her feature debut with the best picture Oscar-winner film by Steve McQueen where she portrayed the role of slave Patsey. 12 Years A Slave was based on the memoirs of Solomon Northup.
The 31-year-old actor will next star in the JJ Abrams-directed Star Wars: Episode VII and will lend her voice to Jon Favreau's The Jungle Book.