Sydney Sweeney has admitted it was “terrifying” filming scenes in creepy catacombs for her new horror Immaculate.

In the new movie, the Euphoria actress plays an American nun named Cecilia who moves to a convent in Italy and discovers its dark secrets.

In one sequence, Cecilia ends up being chased along the dark passageways underneath the convent, and Sweeney told People that was a particularly “creepy” day at work.

“Being able to film in actual catacombs, that was really terrifying and haunting and a technical experience that we had because you only could be down there for so many minutes because of the air quality, and only so many crew members could come down with you,” she explained. “It was just creepy, too, seeing everything that was down there.”

Over the course of the film, Sweeney’s Cecilia becomes covered in more and more blood, and the Anyone But You star revealed she forgot she had it on after a while.

“It is very sticky, and it’s usually cold,” she said of the blood. “The worst is getting it put on you, but then after a while, you’re fine. You forget that you have it on… But then the removal process is extensive.”

Elsewhere in the interview, Sweeney shared that she was a fan of her “comfy” nun costume, but not the habit because it would “crush your ears in a weird way”.

Immaculate is in cinemas now.

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