Ben Barnes Crowned Prince Caspian

On Set for Narnia

"There are a lot of shenanigans on a set when you have people who are half-horse," Barnes joked.

Watch "Popcorn" with Peter Travers on ABC News Now at 8:45 P/ET to see the full interview with Ben Barnes.

(Murray Close/ Disney Enterprises, INC)

He says he had just "a week or two of Narnina bootcamp," which included "horse riding, sword fighting and dialect training" to prepare for seven months of filming on location from New Zealand to Europe.

"They take us to these unbelievable locations which look CGI, even when you're there with rivers and pebble beaches and fern forests and snow-capped mountains and a sunset beyond that, and you're standing there thinking 'I am the luckiest man on the planet,'" he said.

Barnes also said he was surprised by how little "green screen" was actually used in the fantasy film. For characters like Trufflebadger (Ken Stott) he explained that an actress dressed in all-green would crouch and move around the set like a badger, "so you have someone's eyes to look into."

"The tough part is when you literally have to have a conversation with an orange dot and someone's feeding you the lines from 10 yards away," Barnes said, referring to the challenges of acting alongside Reepicheep the field mouse (the voice of Eddie Izzard).

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Though he expected it might be difficult to be a newcomer joining an established cast from the first film, he says he couldn't believe how much on-set life was actually like a Disney movie.

"I remember my first walking into the production office and they were playing table tennis with each other, and sharing a bucket of ice cream. ... It was a lovely environment," he said.

The only thing he could remember being frustrated by was trying to get the horses to stand still while he delivered his lines.

Still Grounded, for Now

Barnes grew up in a family of doctors in London, studying theater and music throughout his childhood.

He said the only thing he lied about to get the part was being able to ride a horse, and he recalled phoning his mom afterward and asking if in fact he had ever been riding. He joked that he was relieved when she produced a photo of him on Shetland pony at age 6.

Looking back, he said the movies that inspired him most included "everything from 'The Sting' and 'Some Like It Hot' through to 'The Shawhsank Redemption' and 'Spinal Tap' and 'American History X.'"

Though he had made it onto the cast of the U.K. production of the hit play "The History Boys," when the Narnia casting agent found him, he was still relatively unknown.

His once-forgotten teenage stint with the boy band HyRise is now creeping back onto the horizon amid Barnes' press blitz for Prince Caspian, to his dismay.