Alexander Skarsgård said that one of the main reasons he took this role was to impress his father Stellan Skarsgård. He said, "My dad is a massive Tarzan fan. Growing up, we had these VHS cassettes of the Johnny Weissmuller films, and that was my introduction to the character. But those films are seventy years old, and so much time has passed, that I think mine is a fresh take. I'll never compete with Johnny Weissmuller, but I just wanted to impress my father. He was thrilled. He was more excited than I was." Oddly enough, his father was considered to play Tarzan in Greystoke: la leyenda de Tarzán, el rey de los simios (1984).
A fully CGI character was created for the swinging-through-the-trees and diving-off-cliffs scenes. A Cirque du Soleil trapeze-artist was brought in to model the proper form and motion for the animators.
Alexander Skarsgård's first cheat meal occurred more than five months into his training. Skarsgård had been on a very strict diet for five straight months, avoiding any fat completely, as he was in the process of developing an eight-pack. He said, "It was a Sunday, and we were training hard in the gym, and my trainer saw that my will to live was fading. He told me to put down the weights and he took me to lunch. That day he let me order whatever I wanted. I got to eat pizza, pasta, tiramisu. I get emotional just talking about that day." On the last day of filming, the crew congratulated him on the end of his diet by gifting him with a huge "Banoffee Pie," a British dessert. Skarsgård said that to celebrate, he ate the entire pie by himself in a single sitting.
Alexander Skarsgård joked that he would like Tarzan to be drastically different in the sequel because of the heavy workout and diet demands on him. He said, "We have an outline already in which Tarzan gains weight. Tarzan remains hairy and does not have eight pack abs. It has no action and Tarzan eats cake, lots of cake. I wrote it."
Director David Yates said that Alexander Skarsgård was always his first choice for the role of Tarzan. He said, "I knew it had to be Alex really early on. Finding a really good actor with a really good body is actually very tricky. Someone who can act very brilliantly, which Alex can, but also look fantastic without his clothes on, that combination is extremely rare and Alex has both those gifts. The Tarzan in my head was tall and vertical and had real length. I love Alex's verticality, his poise, his grace. It was always Alex for me. I went through the process of meeting other people, but it was only Alex in my mind. We basically built the role for him."