Swedish actor Alexander Skarsgard admits he didn't do very much of the rope work on the new Tarzan film.

Skarsgard, 39, admits that his early attempts "didn't look very good," so he was relegated to taking off and landing.

Skarsgard plays the King of the Jungle opposite Australian actress Margot Robbie's Jane in The Legend of Tarzan, and confesses that a very experienced trapeze artist had to come to his rescue.

Prepare for a thrilling adventure this July in The #LegendOfTarzan. #3D #GIF

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The Legend of Tarzan


, due for release later this year and directed by David Yates of the

Harry Potter

film series, is based upon the fictional character created by Edgar Rice Burroughs.

"It didn't look very good... I'm not very good at that stuff," he laughed to E! Online at South by South West, where he premiered his new movie War on Everyone.

"I took off and did a little bit of it and then I sat in my chair with my coffee."

One area where Skarsgard did excel was in building the body of a man who lives off the land and runs in the jungle.

"I basically had him (a trainer) and a nutritionist. I've never done anything like this before, this extreme. I was just really nervous. It was a big challenge and I didn't know how my body would respond to the training and diet," he explained.

The actor needn't have worried though. Promo photos for the blockbuster show him looking extremely buff, a necessity as he appears shirtless in the film - a lot.

The jungle preys on the weak, but never the strong. #LegendOfTarzan

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His routine for months prior to and during filming included eating "a lot of chicken (breasts)" and completing many "crunches (sit-ups)", with just the one cheat day. But by all accounts his cheat day was well worth the wait.

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Skarsgard recalled his trainer taking him to lunch at an Italian restaurant in Notting Hill, London, and told him to order what he wanted.

"I started crying. He was like, 'Have pasta,' and I had it and then he was like, 'Are you still hungry?' I was like, 'Yeah!' He was like, 'Have a pizza then, have some tiramisu.' It was the best meal of my life," he grinned.

The Legend of Tarzan is out in New Zealand on June 30.