Woody Harrelson initially found it a "bit daunting" on the set of 'War for the Planet of the Apes' because of the sheer scale of the production.

Woody Harrelson

Woody Harrelson

The 55-year-old actor plays the Colonel in the next instalment of the re-booted sci-fi franchise and although he has been part of a major series in the past when he starred in 'The Hunger Games' series he was shocked when stepped onto the film's set which was the size of a "city".

Harrelson had never worked with so much green screen and motion capture technology before - something that is integral to bring the ape characters to life on the big screen - but he soon got used to it with the help of Andy Serkis, who plays chimpanzee Caesar.

In an interview with Collider, he said: "It was a bit daunting, I must say, at first. It took me a little while to get used to it because it was definitely the biggest thing I've ever been a part of, it was like going to work at a city, literally. And probably that many people and dozens of cameras, all different types of cameras, super high-tech cameras, motion-capture cameras, so technically it was wild. I really came to love Andy Serkis, who I think is an extraordinary actor and just a great human being - and all the other actors, we got along great. It was a really cool experience."

Harrelson has long been a fan of the 'Apes' series which began in 1968 with the first film about a post-apocalyptic Earth ruled by talking apes which starred Charlton Heston, Roddy McDowall and Linda Harrison.

The Hollywood veteran - who has just been cast in the new Han Solo 'Star Wars' anthology film - was blown away by the new films 'Rise of the Planet of the Apes' and 'Dawn of the Planet of the Apes' and feels privileged to be part of the third film, directed by Matt Reeves.

He said: " I'm a real big fan of the 'Apes' series - I like the old 'Apes' but I really like these [new ones]. When I saw the first one I was like, "Yeah, incredible, I can't wait to see the second one.' "Then I'm like, 'Holy s**t, that may have even been better than the first one, certainly it was as good,' because a lot of times sequels aren't as good. And then I'm like, 'Geez I can't wait to see the third one!' And little did I know I'd be in it. So I feel really lucky to be a part of it. I think Matt is an incredible, gifted, super smart filmmaker. I don't think there's a lot of people who can pull off what he's doing, it is so humongous."