After a huge opening weekend in the box office, everyone is talking about horror movie It.

Based on Stephen King’s classic novel, the plot follows a shapeshifter who frequently takes the form of a clown named Pennywise, as he haunts the children of a small town in Maine.

Pennywise is played by 27 year-old Bill Skarsgard in the film, who looks nothing like the creepy clown in real life. However, you might be surprised to learn that Pennywise’s iconic creepy smile in It (as pictured above) is not achieved by lip prosthetics but a trick Bill himself is able to do.

He explains to Conan how in his childhood, he used the demonic smile to frighten his little brother after learning his older brother Gustav was also able to point his lip.