LOS ANGELES -- Nicholas Hoult gets to do plenty of stiff legged walking and depressing moaning as a zombie in the new film "Warm Bodies." But when his character gets the girl in the end, it's not to eat her brains but to win her heart.

The young British actor's task was to make it believable that a guy who only grunts and groans could make this bizarre take on a "Romeo & Juliet" relationship work.

"I think for most men, grunting and groaning is how we want to communicate," Hoult says with a smile. "That was something that attracted me to the film. It's one of those strange roles that don't come along very often.

"As I read it, I knew there was a lot of strange stuff that I would have to think about to make this work and make the audience care for my character and want to see him succeed."

To prepare for the role, he watched a lot of zombie movies, took some zombie classes and then trusted his instincts when he got on the set.

Hoult is only 23, but he has plenty of past work that helped him tune his instincts. He started acting when he 7 and has already appeared in "About a Boy," "Clash of the Titans," "A Single Man" and "X-Men: First Class."

This year, along with "Warm Bodies," he stars in the upcoming "Jack the Giant Slayer."

The zombie classes helped him get past the embarrassment of walking like a zombie. He became so comfortable he found himself slipping into the stilted gate when he was on a treadmill or just walking down a hotel corridor. The toughest part was the zombie run.

"My mates got a good laugh when they saw me trying to run," Hoult says.

Not every decision he made to play a zombie proved wise. Hoult suggested to director Jonathan Levine that zombies probably wouldn't blink. He agreed and that became part of his performance. Hoult would later rue that suggestion as he found himself straining to keep his eyes open in long scenes.

It might seem odd that anyone with a pulse could love a zombie, but Hoult says his zombie offers his true love protection, hope and a good sense of humor.

In a romance, a boy -- dead or alive -- needs someone to love. The selection came down to five actresses, including Teresa Palmer.

It was obvious to Hoult the Aussie actress had the bubbly energy the role needed to counter his nearly no-energy work as a zombie. He knew she was the right person when they read a scene together.

"At the end of the scene she gave me a little smile and a nudge and a laugh. It kind of made me smile. That's when I thought this is the girl that can definitely make our kind of different zombie movie work," Hoult says.

Palmer, whose credits include "The Sorcerer's Apprentice" and "I Am Number Four," was attracted to the project because she would play a strong female character, something that's not usually the case when zombies come chomping.

"I'm not a fan of the damsel in distress. I like the empowered woman. All the women in my life are very strong and can handle there own. Certainly, Julie can," Palmer says. "She knows how to shoot a gun and protect herself. I love that's she's feisty enough to try and escape her situation."

The concern Palmer had was how she would be able to play scenes with someone who could do little more than grunt.

The answer came from Hoult, who was able to convey so much emotion with his eyes, face and body.

Hoult's face was so expressive -- especially when he gave her a shocked/enamored look -- that Palmer often had trouble not laughing.

Palmer always saw "Warm Bodies" as a love story that just happened to have zombies. But it took her awhile to pick up all of the subtle references to "Romeo & Juliet."

It finally hit her in the scene where she tries to guess her zombie suitor's name. All he can remember is that it starts with an R.

"I am guessing and say Richard and Robert. Then I say Romeo. Jonathan Levine told me I shouldn't actually say Romeo. That's when I got it," Palmer says.