Bill Skarsgard says he developed the unsettling smile he uses as Pennywise the evil clown in It around 17 years ago, when he was just a child.
During a US TV appearance, the 27-year-old was asked by Conan O'Brien to explain "the most evil, demonic smile in all of horror."
Skarsgard is currently scaring audiences worldwide with the smile in the record-breaking horror movie, but revealed that he first did it in order to scare one person in particular.
"My older brother Gustav... had this ability to point his lip in a very strange way," he said, adding that he later realised he had the same ability.
"For some reason... I was maybe 10 years old... I came up with this character, Yodigan. I would pull my t-shirt up over my head... and I would do this face, and chase my little brother."
It is currently playing in New Zealand cinemas.
Newshub.