Sally Hawkins, the Oscar-nominated star of “The Shape of Water,” will take her first executive producer role, on “Cordelia,” a psychological thriller about a young woman who is haunted by past events and who starts to unravel when left alone in her apartment.

Antonia Campbell-Hughes (“Lead Balloon”) stars as Cordelia. She co-wrote the screenplay for the movie with Adrian Shergold (“Funny Cow”), who directs.

Veteran British actor Michael Gambon (“Harry Potter”), Catherine McCormack (“28 Weeks Later”), and actor and musician Johnny Flynn (“Genius”) round out the cast. Georgina Lowe (“Mr Turner”) will exec produce alongside Golden Globe-winning Hawkins.

The titular Cordelia lives with her twin sister, Caroline, and Caroline’s new boyfriend, Matt, in a basement flat in one of the less salubrious parts of London. She is trying to cope with them, a stalker, and neighbors including a mysterious cellist and an eccentric old man, Mr. Moses (Gambon).

More than a decade earlier, Cordelia was a promising actress when a routine journey changed her life forever, an episode that has left her guilt-ridden. The film follows her over a weekend in which Caroline and Matt have gone away. As she attempts to keep to her usual routine, she starts to unravel and, as she attempts to keep her fragile mind together, to question whether certain events are real.

“Antonia and I wanted to explore one weekend in this character’s life, where everything starts to implode for her,” Shergold said. “Did this happen? Is this weekend real? Or is it a figment of Cordelia’s imagination?”

Shergold’s film “Funny Cow” gets a U.K. release through eOne, starting April 20. Kevin Proctor, who produced that picture, also produces “Cordelia” through his StudioPow shingle.

“While working with Adrian on ‘Funny Cow’ we decided that our next collaboration would be something distinctly different,” Proctor said. “Adrian and Antonia have written a unique story with a tone and vision that keeps audiences on the edge of their seat.”

Filming starts in mid-April with a five-week shoot at Twickenham Studios. Kodak and Twickenham Studios are among the production partners.