Actors Julianne Moore and Elle Fanning are set to star together in Rebecca Miller's upcoming film, Moonsong: A Life In Seven Verses, which is the story of famous children's book author Margaret Wise Brown. Based on the book Margaret Wise Brown: Awakened by the Moon by Leonard S Marcus, Moonsong is Miller's ninth film.

Brown is one of the most beloved children's book authors. Her popular works of the 1940s, Goodnight Moon and The Runaway Bunny, are still being read before bed and in classrooms across the world. Moonsong will begin production in the first half of 2027.

Moore, last seen alongside Sydney Sweeney in Echo Valley (2025), just completed filming for Tom Ford's Cry to Heaven and will next be seen in Jesse Eisenberg's The Debut. Fanning, meanwhile, stars in and produces Margo's Got Money Troubles. She will next be seen in The Hunger Games: Sunrise on the Reaping, The Nightingale, which she stars in and produces with her sister, Dakota Fanning, and in Discretion, where she stars opposite Nicole Kidman.