When a South Korean monk performed a Buddhist ritual for a wildly popular K-pop boy band, it was the most unusual ceremony he had ever held. His mission: to guide the souls of the band to peace and rebirth. The band were long gone - or rather, they had never been alive, except in the fictional world of the animated Netflix hit K-pop Demon Hunters.

Still, the YouTube video went viral. Although cast as villains, the Saja Boys have won a devoted following for their gorgeous looks and swagger. Even their name - saja - translates to 'angel of death', among other things.

The live-streamed service, a genuine Buddhist rite known as Chondojae usually performed by monks for grieving families, lasted more than two hours and drew more than 4,000 viewers - more people than he had ever seen for a ceremony, even offline, says the monk, a virtual YouTuber who prefers to remain anonymous.

As K-pop Demon Hunters tops every chart - Netflix says it has become its most watched movie ever - Koreans are revelling in the moment. Made and voiced by Korean-Americans, and produced by US studios Sony and Netflix, the film's inspiration is deeply Korean.

It's a tale about mythical demon hunters whose power comes from their music - in this case, that's a sassy K-pop girl band called Huntrix. And of course, the soundtrack that fans across the world are now singing along to every day is rooted in South Korea's biggest export: K-pop.

All of this has sparked a frenzy in South Korea, like in so many other places, a fascination with the Korean culture the movie centers, and even a little bit of FOMO - because, unlike in the US and Canada, there are no plans yet to release the movie in cinemas here.

More than two months after its release, the film's momentum hasn't slowed – in fact, it's spilling into cinemas. In North America, special 'sing-along' screenings have made K-pop Demon Hunters Netflix's first number one film at the box office. Now South Korean fans are clamouring for the same experience, saying online and offline, 'I want to sing KDH in a cinema!!'.

With the excitement still brewing, K-pop Demon Hunters recently received a spotlight at the Busan International Film Festival, announcing limited sing-along screenings much to the delight of eager fans.