Hart's character leads a gang of stray pets living in the sewers of New York City. And the actor-comic jokes that he went method for the role. "As a thespian nothing is easy," he says. "You have to go to a dark place with anything you do. Being a fan of Daniel Day Lewis, you have to invest in that character. So I was a rabbit for almost two years. A bunny suit, carrots, carrot juice. I went and spent a lot of time with some bunnies. I only ate lettuce for like seven months before filming this movie!"

Kevin Hart at The Secret Life Of Pets PremiereKevin Hart at The Secret Life Of Pets Premiere

He goes on to comment on getting the character's physicality. "I didn't want to use my fingers," he continues, "because I was like, 'It's no fair, bunnies don't have fingers!' So I just wore mittens for like that seven-month period. I made a thumping noise because bunnies thump. And I just hopped a lot. I hopped a whole lot. And when it came time to film, I had the mindset of a bunny. And then I realized that I was in a sound booth, and I didn't have to use any of that s**t!"

Clearly, no one riffs quite like Hart, and he brings his snarky sense of rambling humour to the movie. But there were things about the character that he identified with. "What I relate to with Snowball is the self-deprecation," he says. "And there are moments in this movie where Snowball addresses things before other people do. Those are things that I took, from me and my stand-up, and put them within the building of the character. I also love the fact that he is a leader. I'm very much a guy who can put a plan into place and get people to believe the plan and sacrifice to get there and reward you when we do get there."

Hart does realise that it's a bit ridiculous to look for depth in a cute little bunny, but he approaches all of his roles with the same focus. "I don't just do things just to do them," he says. "I talked to the director. I was like, 'I don't just want to play the guy because he's funny. What's the foundation?' I have to put depth to it. And that's with any movie that I've done. I love Snowball!"

Watch the trailer for The Secret Life Of Pets: