Warning: This article contains spoilers for Immaculate.

Talk about one hell of a surprise: Sydney Sweeney brought her grandmothers to the movie's Los Angeles premiere of her wild new nun horror movie Immaculate... but neglected to tell them just how wild the film gets.

The star, who also produced the flick, made sure her Nana and Grandy — who both cameo as nuns in the film — were on hand at the screening so she could see their reactions up close and personal.

"I sat next to them," Sweeney tells Entertainment Weekly. "I was very nervous to see what they were going to think. I got a few [reactions] of my Grandy leaning forward looking at me going, 'Oh my God, Sydney,'" she says, cackling with delight.

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Immaculate follows Sweeney's Cecilia, an American nun who seeks a change of pace and joins an illustrious Italian convent. Once there, she somehow becomes pregnant, but when she learns the horrific truth of the convent and her supposedly miraculous pregnancy, she must do whatever it takes to escape. That's where things get very bloody...and very uncomfortable for Sweeney's poor Grandy.

"Definitely during the third act, the killing spree I went on — that got her really bad," the star says.

As for her grandmothers' cameos, Sweeney says "a fun little Easter egg" is that her Nana is actually a pro, having made appearances in all of the projects Sweeney's made with director Michael Mohan: 2018 series Everything Sucks, 2021 film The Voyeurs, and now, Immaculate.

However, both grandmas got in on the on-screen fun this time around thanks to a very special trip to Italy. "It was both my Nana and my Grandy's dream to go to Italy, to Europe. They've never traveled outside of the country that way," Sweeney explains. "So for Christmas, I surprised them with little nun habits and little Italian bells, and I told them if they rung it, then they got to go to Italy."

Neon/Courtesy of Everett

And ring the bells they did. Sweeney says she flew them to Italy, where they stayed for a little over a week and got to explore Rome. "Then I brought them on set and they got to be extras in the church scenes and they got to see me work," she says, adding, "And I get to kind of cement that memory in film forever for me to be able to watch — it's amazing."

Immaculate is now playing in theaters and also stars Álvaro Morte, The White Lotus' Simona Tabasco, and Benedetta Porcaroli.

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