IT made its way into theaters over the weekend and is already a huge hit and is likely to be considered a modern horror classic. Much of that has to do with the performance of Bill Skarsgard, who plays Pennywise the clown in the new take on Stephen King's classic novel. Now, the actor has revealed the story behind Pennywise's creepy smile, which is actually Skarsgard and not some sort of prosthetic or effect. And he is more than happy to prove it.

Bill Skarsgard recently appeared on Conan to talk about IT and his role as Pennywise. Conan at one point asked about his smile, which is a truly terrifying signature of his new take on the character. Skarsgard revealed that he learned how to do it from his brother and decided to show it off without the makeup for the cameras. It turns out, even without the Pennywise costume, the smile is pretty unsettling. Here's what Bill Skarsgard had to say about crafting Pennywise's smile.

"My older brother Gustav, who's an actor as well, he had this ability to point his lip in a very strange way. For some reason, I don't know how I understood that I could do it as well, I was maybe ten years old...I came up with this character, Yodigan. I would pull my t-shirt up over my head, so you wouldn't see me, and I would do this face, and chase my little brother."

There are a great many factors that contributed to the success of Andy Muschietti's IT, but Bill Skarsgard's terrifying take on Pennywise is very close to the top of the list. From the earliest stages of marketing for the movie, his creepy clown helped sell people on the idea of this new take on IT, which has proved to be a bigger hit than anyone expected. The movie made $123 million opening weekend and has already made $209 million worldwide on a production budget of just $35 million. Creepy or not, Bill Skarsgard has every reason to be smiling right now. Especially since he is probably going to see some of that box office take in his bank account with his likely huge payday for the IT sequel.

New Line Cinema hasn't officially announced IT: Chapter Two yet, but writer Gary Dauberman has been hired to pen the script for the sequel and director Andy Muschietti is expected to return. Bill Skarsgard has already said previously that he is signed on to do the sequel. Afterall, what would an IT sequel be without the creepy clown that made it work so well the first time around? So we can look forward to a lot more of that unsettling smile when the sequel arrives, which is likely to hit theaters in 2019. Be sure to check out the clip of Bill Skarsgard showing off his Pennywise smile for yourself below.