At 39, True Blood's Swedish-born star Alexander Skarsgard has become the latest actor to play Tarzan on the big screen. And he's not quite sure how he got here. "I don't really have a three-year plan or a five-year plan," he says. "I don't know what's next, and that's what I find quite exciting. I dig it."

Skargard and his lead cast co-stars

This loose approach to his career comes from his childhood. "I grew up in a very urban, bohemian family where everyone was a hippie or a pacifist," he says. "It was artistically and intellectually stimulating, but they were definitely not into outdoor sports or activities."

His actor father Stellan (The Avengers) says that he laughed when he heard that his son would be playing Tarzan. "And he laughed too," Stellan says. "I mean, it was not meaningful at all, it was extremely comic. I can't explain my kid being Johnny Weissmuller. But I'm sure it's great. He's a much better actor than Johnny Weissmuller!"

To prepare for the role, Alexander entered a strict diet and exercise regimen. First he cut out gluten, sugar, dairy and alcohol, then he ate 6,000 calories a day and lifted weights. This got him ready for all those shirtless treetop acrobatics. "We did quite a bit of the vine-swinging ourselves," he says. "But they also had a 3D scan of my body, so they had Augusts Dakteris, one of the greatest trapeze artists in the world, who came in. We sat there with our coffees watching him do these amazing stunts on the vine. Then they would remove his body, use his movements, and replace it with my body. So I'm watching the movie, and I recognise myself doing these Olympic stunts. But Augusts deserves that credit!"

After starving himself for months, he was happy to fall off the dietary wagon. "When we wrapped the movie, I went straight to my father's house in London," Alexander says. "My dad loves to cook, so I spent four days on his couch just being fed. It was bone marrow, fried mozzarella, pasta, red wine. Then five months later our producer called me and said, 'So we have this little scene we added at the end of the movie that we need to shoot. It's about a five-second scene, so can you go back on that diet for that scene?' I went back on the diet."

Which of course gave Alexander an idea for the sequel. "If we make another one," he says, "it could be 10 years later, so maybe he's out of shape! He's in a hammock the entire movie. He just drinks pina coladas."

Watch the trailer for The Legend Of Tarzan: