"Pretty mental." That's how Brit actor Aaron Johnson describes seeing himself up on the big screen as a superhero in "Kick-Ass." Those two words also sum up the leap his career has taken recently, as he's gone from little-known child actor to the star of upcoming films like "Nowhere Boy," in which he plays a young John Lennon, and "Kick-Ass," set to hit theaters on Friday (April 16).

His starring role in the much buzzed about "Kick-Ass" is a meaty one. Johnson plays Dave Lizewski, an ordinary teen turned green-suited defender of the peace, with no superpower other than his desire to do good -- and crack some skulls in the process. Of course, the only skull that ends up getting cracked in the beginning is his own. But the 19-year-old actor embraced the challenge and didn't mind looking a little silly in the process.

"I really enjoyed the idea of this kid being unique and original and he thinks he's really cool," he told MTV News. "The more ridiculous I looked, the better. I always think I looked like a green gummy bear ... a 'green condom' is what I get called quite a bit. It was a good laugh."

A trained dancer, Johnson choreographed his many fight scenes -- designed by vets of "300" -- as if they were dance routines. In that sense, he worked hard, but he was also free to eat as much junk food as he wanted and to avoid the gym at all costs. "Just be ordinary kids" was director Matthew Vaughn's advice to his cast, which includes Nicolas Cage, Christopher Mintz-Plasse and Chloe Moretz.

"We literally had to do nothing," Johnson laughed.

With "Kick-Ass" poised to make Johnson one of 2010's breakout stars, audiences should be keeping an eye out for "Nowhere Boy," which arrives in October. The coming-of-age tale focuses on the period during which a teenaged Lennon formed the friendships and musical talents that would eventually lead to the creation of the Beatles. And then there's the talk of a "Kick-Ass" sequel -- no doubt premature since the film hasn't yet been released but rampant because it's getting such early critical praise. Johnson is excited about returning to "Kick-Ass" territory, and has even got some ideas for the next story line.

"Obviously, you always want yourself to become the big bad boy," he said. "I quite like the idea that Kick-Ass is always Dave Lizewski. You can't make him some crazy superhero who's going to be strong. Maybe [Moretz's] Hit Girl can help Kick-Ass train because he definitely needs to know how to fight."

Check out everything we've got on "Kick-Ass."

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