Bill Skarsgard had nightmares for "weeks" after he finished filming 'IT'.

The 27-year-old actor stars as the iconic horror villain Pennywise the Dancing Clown in the new Andres Muschietti-directed movie, and he's revealed the film continued to haunt him even after the shoot wrapped.

He shared: "It was weird. I really enjoyed myself doing it, but the day after we wrapped, I went back home to Stockholm, Sweden, and it's always a weird experience when you work really hard on something and then you go back to regular life at your childhood home.

"And that's when I finally realised what an impact the character had had on me. For the following two weeks I would have these really disturbing dreams about Pennywise.

"It was very strange, it was almost like a really slow exorcism to completely let go of him."

Bill likened his post-filming experience to ending a "very destructive relationship".

Explaining the scenario to non-actors, he told PEOPLE: "The closest thing I can liken it to is being in a very destructive relationship, because you never really realise you're in one until you're out.

"And then as soon as you're out of it, you're like, 'Oh my God, I can see it all so clearly now.' Doing characters is almost like being in a relationship with a made-up person, and you don't really see the journey clearly until it's over."

Despite the subsequent nightmares, Bill insisted he relished his time on set.

He said: "I did have so much fun with the character, and I'm really looking forward to getting back under that clown make-up for the sequel."