When Bill Skarsgard was cast as evil clown Pennywise in the new film adaptation of Stephen King's It, the internet erupted because he's nothing like Tim Curry, who starred in the 1990 TV miniseries. So Bill Skarsgard was pleased when the first trailer became the most-viewed ever.

Bill Skarsgard in 'It'Bill Skarsgard in 'It'

"I was surprised and shocked," he admits. "I knew people were excited about the film and there was a lot of interest in it, but I had no idea how much. And I think the film is really good and does a lot of justice to the novel. I think and hope that fans will like it!"

To prepare his audition for the role, Skarsgard says that he spent three days "playing around with different things and voices and facial expressions". He goes on to admit that "there were a lot of people who had to be convinced that I was the right person for the job, so there were a lot of auditions. Once I got the job I had to embody the character, putting the make-up on and seeing how my face reacted to it and moved."

Watch the trailer for 'It' here:

And he had a clear idea for playing Pennywise. "The concept of unpredictability is something that's very scary to me," Skarsgard says. "If you have explosiveness and quick changes, it's something that's very unsettling. I wanted the character be almost like when you're about to pop a balloon. In the character, if something happens, it's super explosive. But there's an unpredictability, as if you're pulling something back and at any moment it might snap."

He says that creating this atmosphere on-set was fun. "The kids were all little actors, even when we were doing the first scene," Skarsgard says. "So the first time Jack Dylan Grazer [who plays Eddie] sees me, he goes, 'Oh whoa! Great!" And I was so in my own head, because we were shooting this scene. I'm mocking his asthma and his breathing. He's crying and he's gagging and I'm drooling all over him. It's this really intense scene. 'Cut!' I'm like, 'Are you okay, Jack?' And he was like, 'Yeah man, awesome! I love what you're doing!'"

More: Bill Skarsgard scared the children on the set of 'It'

Indeed, Skarsgard is aware that he's basically trying to traumatise the audience. "It's a strange thing to come to terms with," he laughs, "that if I really succeed with this, people will have nightmares about this character for a really long time. Ultimately it's all just fun and games, and the world is a much more terrifying place than Pennywise can ever be."