Lionsgate has found its Margaret -- and her mother -- as young Ant-Man actress Abby Ryder Fortson and Oscar-nominated actress Rachel McAdams have signed on to star in a movie based on Judy Blume's beloved novel Are You There, God? It’s Me, Margaret, Collider has confirmed.

The coming-of-age movie hails from writer-director Kelly Fremon Craig, who showed heightened sensitivity to the issues young girls face during puberty with her 2016 film The Edge of Seventeen. She'll also produce Margaret alongside Julie Ansell, Richard Sakai, Amy Brooks and Blume herself, as well as James L. Brooks' Gracie Films.

It’s Me, Margaret follows a sixth grader who moves from the city to the suburbs and prays to God to watch over her as she enters puberty and becomes anxious about the changes her body is going through.

Blume signed off on the adaptation after Fremon Craig flew down to meet with the famed author in Key West, Florida, and when it came time to pitch the project to studios, Lionsgate reportedly transformed a conference room into an 11-year-old girl's bedroom -- replete with pictures of executives as 11-year-olds -- in an effort to woo the director.  Meredith Wieck and Chelsea Kujawa will now oversee production for the studio.

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Image via Disney/Marvel

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"This title was an anthem when we first read it as teens, and it remains timeless and relevant because nothing has captured the coming-of-age experience with the same authenticity, truth and respect. For that reason, Judy Blume is a beacon for women and girls," Lionsgate's Erin Westerman said in a statement when the project was first announced in March 2020.

"Kelly Fremon Craig is a filmmaker we have adored and chased for years, and James L Brooks is a hero to us all. Together, they delivered an adaptation that captures all the scope and potential of the title; the themes of identity, loneliness, confidence and kindness are urgent, ageless and more necessary today than ever before," Westerman added at the time.

The role of Margaret is a huge get for Fortson, who is best known for playing Cassie Lang in Ant-Man as well as Ant-Man and the Wasp. She also played a younger version of Kathryn Prescott's character in A Dog's Journey, and starred alongside Jessica Rothe in 2018's country music drama Forever My Girl. Fortson's TV credits include Transparent, Togetherness, Room 104 and Tales from the Loop.

McAdams is coming off the hit comedy Game Night and the popular Netflix movie Eurovision, in which she also performed several memorable songs. She is also due to reprise her role in Marvel's Doctor Strange in the Multiverse of Madness.

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