The Welsh national anthem helped a singer with her role in horror film The Exorcist: Believer.
Helen Leahey grew up in Cynwyd, near Corwen in Denbighshire, but has been based in Germany for many years.
"I'm from Wales originally and I grew up speaking Welsh until I was about 10 in school. So Welsh was close to being my mother tongue when I was small," she told Sky News.
The musician provided the sounds for the demon in the new Exorcist sequel, which was released in cinemas last month, and the anthem, Hen Wlad Fy Nhadau, played a part in getting the sounds just right.
"It had to sound different, other-worldly, and Welsh is not a language that everybody can speak, it does have a sort of unique sound to it," she said.
"I was a little bit sort of on the spot I suppose and thought how can I bring this across without speaking gobbledygook and nonsense.
"And I thought OK, with the Welsh national anthem, and if I do it backwards it's going to give me that sound that I'm looking for and that's what I did.
"I wrote it down and read it backwards in a demon's voice and that's how it came to be."
Ms Leahey was the first Guinness World Record holder for the lowest vocal note by a female in 2018.
"I was really proud, especially being the first and what was really nice afterwards actually was once I'd done that then all of a sudden other women were contacting me around the world," she added.
"It just seemed to sort of empower women with strong, deep female vocals to show off and shine too and I just thought that was really nice."
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Ms Leahey said the uniqueness of her voice had helped her gain the role.
"With this film, the demon's female...so they were looking for a voice that does sound female," she said.
"I assume they just typed into Google 'deep female vocals' or whatever and they found me. Then I got asked if I wanted to audition and I did and one thing led to another really."
The Exorcist: Believer is out now in cinemas.