The time actors went through painful surgery to become Na’vi for Avatar

Sweated beaded on Sam Worthington forehead. The pain in his leg was manageable as the screws entered his flesh and bones, but he knew the process would soon become excruciating.

“Brace yourself Mr Worthington,” said the surgeon.

He did, knowing it would make no difference.

His scream obscured the loud crack as his leg was stretched eight inches.

He closed his eyes. The first leg stretch was complete, but there was another four hours of painful surgery that would transform him into a nine foot tall blue alien in time for the day’s filming.

“As an actor, you can often be exposed to tedious make-up application,” explained veteran actress and Avatar co-star Sigourney Weaver in a 2011 Wogan interview.

“For Ghostbusters, it took ninety minutes each morning to transform me into a cellist.

“But, such was Jim [Cameron]’s dedication to realism with Avatar that we had to go through the surgery every day.

“Leg-stretching, skin-dying, skull-reshaping – four hours in the morning, four in the evening, but it was worth it, I guess.”

Initially, James Cameron planned to create the Na’vi digitally, but the resulting effects failed to convince using the new 3d technology he wanted to use.

“Looked like crap is what they did,” said the Titanic director in a 2012 Wogan interview.

“2d – fine, because everything is flat, so the computer graphics, which were also flat, fit right in.

“But you make it 3d and you’ve got all the trees and humans and machines in 3d and then these 2d goddamn Na’vi.

“Looked like butt. No way we could use that.”

There was a suggestion that the special effects team develop new ground-breaking 3d effects.

“Who has time for that? No, screw it. You get the actors in early and surgically reconstruct their bodies to turn them into Na’vi, otherwise, what’s even the point of making the damn picture?”

The film went on to become the biggest grossing film of all time and was nominated for a host of Oscars. However it was not without its toll.

“Yeah, there was a bunch of extras,” continued Mr Cameron.

“We didn’t have time to transform them into Na’vi each day, so we just transformed them into Na’vi at the start of the shoot and the idea was to transform them back at the end of the shoot but, you know, everything overran and we blew the budget and you know, we couldn’t get round to it.”

Consequently, that is why, in a remote area of New Zealand, there are a small community of film extras who live their lives as Na’vi.

They have little contact with the outside world except for the small group of hobbits nearby with whom they occasionally trade.