The basic premise of the comedy, according to early reports, is the story of a woman who loses her faith in God after a plane crash. While she is living "the life of a sinner" in Las Vegas, she finds her way back to her faith.
She described the upcoming film as a "nice Christmas story" on her Tumblr.
Mandate Pictures has acquired an original screenplay and Mason Novik, best known for "500 Days of Summer", will produce the film.
Diablo, who won an Academy Award Winner for Best Original Screenplay for "Juno", will also work alongside Mandate president Nathan Kahane, who she collaborated with in the past on "Juno" and "Young Adult".
Kahane said in a statement, "Having been in the trenches with Diablo and Mason on Juno and Young Adult, we immediately jumped at the opportunity to partner with them again. It's an honour to be a part of Diablo's transition as a director."
Cody, who has dedicated her life to writing since 2005 after her box office hit "Juno", is excited to step into the director's shoes.
"I wrote 'Juno' in 2005. I've been a writer ever since; sometimes a writer-producer, but a writer all the same. And now I'm … something else. If I hear a certain type of music for a scene, I don't have to shyly suggest it," she expressed in Tumblr.
"Lamb of God" will be released by Paramount Pictures. Mandate stated that they will "begin casting right away".