Finn Wolfhard found voice acting "frustrating" before starring in 'Pinocchio'.

The 19-year-old star lends his voice to the role of Candlewick in Guillermo Del Toro's stop-motion take on the classic story but was able to avoid his usual frustration by working together with Gregory Mann – who voices Pinocchio.

Finn told Screen Rant: "I had such a good time doing this movie, especially because I actually got to work in a booth with Gregory for one of the scenes. That just helps so much, because you get to bounce off someone.

"Usually, when it comes to voice acting, I get really frustrated because it's a very hard thing to do. Some people are just so good at it, (but) I've always been very in my head because I feel like I work best when I'm around or bouncing off other people or whatever.

"When it's just you in the booth, you're kind of like, 'Oh, God...' But Mark (Gustafson) and Guillermo are so good at relaxing me. Yeah, they're great."

The new movie has darker themes than the 1940 Disney version and Guillermo doesn't want it to be considered as a film for children.

He said: "People ask us if it is for kids (and) we say, 'It's not made for kids but kids can watch it if their parents talk to them.'

"It's not a babysitter movie, it's a movie that will have kids ask questions."

The movie is set in Italy when the country was ruled by Fascist dictator Benito Mussolini and Guillermo said that the time period was deliberately chosen so he could explore the theme of "obedience".

The 'Mimic' director said: "Obedience to me is where you are told to follow something whether, on a religious level or social level, that you don't understand, that is a big mistake. Disobedience with consciousness is always the beginning of thought, of soul and self.

"When I was a practicing Catholic, not lapsed as I am now, I used to think about where the human soul lies – it lies in the freedom of choice. The choice is to be human."