The 31-year-old Oscar winner is set to star and produce the romance flick about a young Nigerian woman, Ifemelu, who separates from her high-school sweetheart, Obinze, as she travels to America to get a college education.
Nyong'o will partner with Brad Pitt's production company Plan B, along with D2 Productions and Potboiler Productions, for her role as producer in the film.
"It is such an honor to have the opportunity to bring Ms. Adichie's brilliant book to the screen," Nyong'o said in a statement. "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, humor and heart."
Nyong'o, who is of both Kenyan and Mexican decent, made her editing and directorial debut in the 2009 documentary In My Genes.