The actor told SFX that his villainous character Loki feels such a strong level of pain and hatred that he became tiring to play at times.
"It was a huge undertaking because it was an amazing challenge and an amazing privilege to play the bad guy," he explained. "It was a challenge to dial up the menace and I was exhausted when I finished filming.
"It's funny how negative energy is so exhausting, and it was certainly a challenge to cultivate Loki's hatefulness every day. I had to get inside his reservoirs of pain and make that feel real.
"Hating is exhausting; it's much more exhausting than loving, and that's what took it out of me - as well as some of the physical challenges that we all undertook."
"He was incredibly open and that's what you want as an actor: you want to collaborate. Everyone has a certain level of ownership of their character and Joss was very respectful of that possession.
"He would constantly ask us, 'Does this feel right for your character? Does this feel true to you? Is this in your voice?'"
It was been confirmed that Whedon will return to write and direct the upcoming sequel to The Avengers.
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Watch Hiddleston discussing The Avengers with Digital Spy below: