The Bell Jar star cast is set to expand, with Ella Beatty speculated to join the Billie Eilish and Carey Mulligan starrer. The film, to be written and directed by Sarah Polley, is a film adaptation of American poet Sylvia Plath's semi-autobiographical novel.

Eilish, in her acting debut, will play protagonist Esther Greenwood, with Mulligan playing her mother. Beatty's character has not been disclosed yet.

The novel, originally published in 1963, charts a young woman's descent into mental illness as societal pressures pile up. The book parallels Plath's experience as she was undergoing depression and ended her life a month after the novel's first UK publication. The book is hugely popular worldwide with translations in over 40 languages.

Beatty, who made her feature debut in 2025 with If I Had Legs I'd Kick You, also starred in the TV shows like Feud: Capote vs The Swans (2024) and Monster (2026). Her last feature appearance was in Act One, written, produced, and directed by Sophia Takal.

Plan B, Joy Coalition, and Studiocanal are producing the upcoming film.