The movie will be based on a novel due for release in 2017 and written by Wendy Walker, reported Deadline.
Witherspoon formed her production company Pacific Standard with Bruna Papandrea in 2012. They have produced films such as "Wild", "Gone Girl" and "Hot Pursuit" in the past.
Meanwhile, Witherspoon is to play Tinker Bell in upcoming Disney film "Tink".
She will also appear alongside Nicole Kidman in HBO limited event series "Big Little Lies".
It was also previously announced that Witherspoon will narrate Harper Lee's long-awaited "To Kill a Mockingbird" sequel.