Lively (Gossip Girl) will have a starring role in this movie written and directed by Rebecca Miller (The Ballad of Jack and Rose).
The rest of the cast will include Robin Wright Penn, Julianne Moore, Winona Ryder, Keanu Reeves, Maria Bello, Alan Arkin and Monica Belluci.
In this dramatic comedy, based on a novel by Miller, a woman questions her life when her husband leaves her for a younger woman.
Filming will begin this month in Connecticut.
Fans can also see Blake Lively in The Sisterhood of the Traveling Pants 2, which will be in theatres on August 8, as well as New York, I Love You, which will be released sometime this year.