EXCLUSIVE: Pretty Little Liars star Sasha Pieterse is set to lead psychological thriller Rosemary, which will recount the tragic story of Rosemary Kennedy “from her perspective”.

Kennedy was the sister of President John F Kennedy and senators Robert F and Ted Kennedy. As a child, she reportedly exhibited developmental delays and in her young adult years is said to have developed behavioural issues. In response, family patriarch Joseph P. Kennedy Sr arranged a lobotomy on her when she was 23 years old, a procedure which left her permanently incapacitated. She spent most of the rest of her life being cared for at St. Coletta, an institution in Wisconsin, and she was isolated from family and siblings for long periods. Kennedy died from natural causes in 2005 aged 86.

Mike Medavoy, the Hollywood vet known for movies including Black Swan and Shutter Island, is helping shepherd the film, which will be written and directed by Cory Todd Hughes and Adrian Speckert, whose scripts to date have included Under Fire, starring Dylan Sprouse, and Foster, starring Ron Perlman.

Emanuele Moretti (Bucking Fastard) and The Motus Studios will produce with Nick Medavoy (The Image Of You) and Kaan Karahan (Winter Spring Summer or Fall); Hughes, Speckert and Mike Medavoy are serving as executive producers. Motus Studios will handle international sales.

According to the team, the contained thriller will “dramatize Rosemary Kennedy’s struggle with mental health, the devastating decision by her father, Joseph P. Kennedy Sr., to subject her to a lobotomy at age 23, and the long–lasting consequences of that choice.”

The film is based on the All That’s Interesting article ‘Rosemary Kennedy, JFK’s Sister Who Was Lobotomized And Locked Away’.

“This film takes a story that has long lived in the shadows of history and places Rosemary at the center, not as a footnote in a political dynasty, but as a young woman with hopes, fears, and a voice that was never truly heard,” Mike Medavoy said.

Pieterse said of the role: “Rosemary’s story has been told in fragments. What drew me to this project is how it explores her as a person, not a symbol, but a fully realized human being with dreams and vulnerabilities.”

Hughes and Speckert added: “This isn’t just a historical biopic. It’s a psychological journey told through Rosemary’s eyes, one that challenges the audience to reckon with how we define agency, dignity, and identity.”

Todd Hughes and Speckert are separately collaborating with Pieterse on an adaptation of popular American novelist Sherrilyn Kenyon’s upcoming urban fantasy book series Infernal Affairs.

Pieterse is best known for portraying Alison DiLaurentis in the Freeform series Pretty Little Liars and its spinoff Pretty Little Liars: The Perfectionists. The former Dancing With The Stars contestant also starred in 2024 movie The Image Of You with Parker Young and Mira Sorvino, a film which was exec-produced by Karahan and associate-produced by Nick Medavoy.