Seated next to the muscle-bound Chris Hemsworth, Tom Hiddleston looks like the wimpier part of the duo. The only similarity they share is that they're about the same height.

That didn't stop Hiddleston from trying out to play the god of thunder in the new Marvel Comics-inspired film "Thor."

"I really didn't want to play Thor. But like every actor in England who is 6-2, I auditioned," Hiddleston says. "I'm not built like a house, so there's no way in Odin's Asgard I could have delivered what Chris has done."

He didn't get cast as Thor, but Hiddleston is in the movie. He plays Loki, the god of mischief, who's Thor's brother. Through his passive-aggressive ways, Loki keeps Earth and Asgard in constant turmoil.

Despite Loki's actions, Hiddleston doesn't consider him a bad guy.

"There are no villains in this world, just misunderstood heroes. I think Loki thinks he is the hero," Hiddleston says. "There's a deeply misguided intention in Loki. If you boil this story down to the barest elements, it's about a father and two sons and both those sons are competing for the love and pride of their father."

Loki is a difficult character. It's never clear if he's out only for himself or -- in a twisted way -- doing what he thinks is right. "Thor" director Kenneth Branagh knew Hiddleston could handle the complexities of the character, having worked with the young actor on stage and in the TV series "Wallander." This is the biggest film role for the British stage actor.

Hiddleston didn't read comics growing up in England, but he played a card game that featured the Marvel characters. That's how he knew he was going to have to deal with Loki's odd costume, which includes a massive pair of horns on his helmet.

"I was quite nervous of how that was going to translate into a real context," he says. "But it really does something to you to wear it."

The heavy helmet covers a large part of his face. Hiddleston was afraid that it would mask his facial expressions. But because of the helmet's design, he had to look out from under it and that gave him an automatic sneer. It was the perfect look for Loki.

In the end, Hiddleston was able to relate to Loki.

"In the Norse mythology, he's known as the shape shifter," he says. "He can appear in many, many guises. So I suppose he is an actor."

Hiddleston's next acting role will be for Steven Spielberg's "War Horse." He'll also return as Loki for the upcoming film "The Avengers."