The Twilight actress will play the suicidal Peyton Loftis in the film adaptation of William Styron's novel, according to New York Magazine.
Stewart first expressed interest in the project in May, describing the part of Peyton as her ideal role.
Hunger Games actress Jennifer Lawrence previously spoke about her desire to play Peyton in an interview with W Magazine.
"I am obsessed with that part," she said. "I have this feeling of protectiveness over characters I want to play.
"I worry about them - if someone else gets the part, I'm afraid they won't do it right; they'll make the character a victim or they'll make her a villain or they'll just get it wrong somehow."
However, Lawrence is too busy to take on the role of Peyton, given that she will spend the next year shooting The Hunger Games: Catching Fire and the follow-up to X-Men: First Class.
Watch Kristen Stewart in the Twilight Breaking Dawn - Part 2 trailer below: