After voicing Batman in 2014's The Lego Movie, Will Arnett was intrigued by proposals to spin off the character into his own adventure, The Lego Batman Movie. "It's very fun to take an iconic character like Batman and play with the rules that have always been there for him," he says. "Keep it consistent in terms of him being good at what he does and having that bravado and machismo but, at the same time, make him a little more flawed and a little bit goofier"

Lego Batman Movie

Arnett says the idea was to see why Batman was so moody in The Dark Knight trilogy. He says there's inherent comedy in the idea that this handsome billionaire has a cave full of great gadgets but is still upset about something. "It made sense within the Lego world to explore that," he says. "And we've tried to expand on that in this movie and really get down to what makes Batman tick. But as you record a few sessions and you get on these tangents, you end up taking the entire story down a road that wasn't necessarily the intended road. It can totally drastically change the narrative just through goofing around."

To create the character, he looked at all of the Batmen who went before. "I'm just really lucky that I've got all of these great guys who played Batman before me," Arnett says. "And the comics before that! And I get to draw on this deep well and just mix and match."

This included finding his Batman's voice, a growly whisper that he says was tricky to maintain. "Vocally, physically, it would get hard," he admits. "After four hours of doing it, I'd be pretty spent, because it doesn't feel great to constantly be talking like that!"

He also enjoyed how this film explores the way Batman and his nemesis Joker, voiced by Zach Galifianakis depend on each other. "I've known Zach forever," Arnett says. "The dynamic we landed on for Batman and the Joker that really works for us - I would describe it as refreshing. It's a little bit surprising. It's not what people are accustomed to with regards to these two characters. We got to try a lot of things. It's very rare when you are working that you do stuff that really makes you laugh on a profound level, especially when you are sitting in a recording booth. But we were making each other laugh. And a lot of the stuff we created in the moment made it into the movie."

Watch the trailer for The Lego Batman Movie: