Radha Mitchell is no Hollywood scream queen, but the 36-year-old Aussie—noted for her leading role in Woody Allen’s 2004 comedy-drama Melinda and Melinda—has taken on her fair share of fierce monsters and supernatural forces. She had her first genre role in 2000’s Pitch Black, playing a downed space pilot trying to survive—with the help of Vin Diesel—a feeding frenzy of nocturnal beasties. Then in 2006 she scored the lead role of a mother trying to save her nightmare-tormented daughter in the video-game spinoff Silent Hill.

In The Crazies, a remake of terror titan George Romero’s cautionary shocker of 1973, Mitchell plays Judy Dutton, a doctor in rural Iowa who’s married to the small town’s sheriff (Timothy Olyphant). Everything is hunky-dory in their quiet community until one of the residents shows up in a daze at the local ballpark, toting a shotgun and bad intentions. Soon afterward, the town becomes engulfed in madness and murder, the result of a military plane crashing nearby and poisoning the water supply with biological weapons.

A full-tilt, no-holds-barred exercise in fear, The Crazies (which opens on Friday [February 26]) should earn Mitchell additional street cred among the dedicated horror freaks still clinging to their Fangoria subscriptions. She isn’t one of them, but their undying attraction to the dark side of movies—and its cathartic appeal—isn’t lost on her.

“I don’t see a lot of these films,” she admits on the phone from L.A., “but since I’ve been making them I’ve gotten more and more interested in the genre. What they say about mass psychology, and why we need to see these films, is kind of interesting to me.

“And in terms of acting in them, it’s always fun,” she says, “because you get to explore all your inner angst and get paid to scream. A movie like that, it’s quite intense, and you have to kind of cleanse yourself from it, in a way, after you finish shooting it.”

One of The Crazies’ most horrifying moments occurs when Mitchell’s character is menaced by a zombielike killer with a pitchfork. It’s the type of scene that could raise the hackles of even the most seasoned genre fan.

“It’s certainly a rough ride,” she says of the film as a whole, “and you’re either signing up for that or you’re not. But what I really like about the movie is it’s a visceral experience that leaves you thinking, as well. Like, what does it actually mean in terms of our lives? Part of the [film’s promotional] Web site leads you to take action if you want to; there’s a petition you can sign that will encourage chemical plants to use safer techniques, so that even if something terrible happens—say, a terrorist attack—millions of people don’t die.

“So I like the fact that the movie has aligned itself with some sort of social-action campaign in a way that Romero would have back then if the Internet was playing the role that it is now. Obviously, nihilism is part of going to see a horror movie, but if you can turn that nihilism into action, it’s kind of revolutionary!”