Freakin' out over Pennywise in 'IT?' Blame Bill Skarsgard

Director Andy Muschietti revealed it was actor Bill Skarsgard's creepy parlour trick with his eyes that made him appear even more convincing as Pennywise.

The 44-year-old filmmaker said he wanted his version of the Dancing Clown to have "something off" with his eyes, which resulted in the actor naturally using his eyes to look in opposite directions, reported DigitalSpy.

"It's entirely practical. Besides from the morphing moments, it's him even the moment where his eye is looking away. I told Bill, 'I want it in both directions, I want you to send your eyes looking away and give a really unsettling look'. He said, 'I can do it', so he did it. What are the chances? It's one in a million and he was cast already. So even in those moments when his eyes move, it was in. In the storm drain when he goes limp with his eyes looking ... up, that's all him," Muschietti said.

The director said no CGI was used to achieve the effect.