Fortson will play Margaret Simon, a sixth-grade girl who is going through puberty and searches the universe for any answers she can find. McAdams is portraying Margaret’s mother, Barbara.
The movie, set up at Lionsgate, will be written and directed by Kelly Fremon Craig. It’s expected to begin production in April.
“Are You There God? It’s Me, Margaret” was first published in 1970 and remains hugely popular among young, budding readers. Blume has long been opposed to screen adaptations of her seminal work, a notable list that includes “Tales of a Fourth Grade Nothing,” “Blubber,” “Forever” and “Tiger Eyes.” However, the upcoming version of “Are You There God?” — especially the casting — comes with Blume’s blessing.
“Abby is funny and tender, strong yet vulnerable.