BEVERLY HILLS, California -- If you went out into your front yard tomorrow and discovered Bruce Willis picking through your trash, would you beat him over the head with a broom? If Avril Lavigne and William Shatner were devouring a bag of Doritos on your lawn, would you call an exterminator?

After this weekend, children and adults might find themselves wishing that Steve Carell, Garry Shandling and Nick Nolte would start running around their suburban neighborhood, knocking over garbage cans.

If it ever does happen, the stars of "Over the Hedge" have one simple request: Be kind to animals.

"Animals do peek over the hedge at my life," laughed Carell, speculating on a visit by his "Hedge" alter ego, a hyper squirrel named Hammy. "They are horrified with what they see."

The latest animated film from the makers of "Shrek" and "Madagascar," "Over the Hedge" follows a motley crew of critters invading suburbia after getting a taste for such delicacies as pizza, popcorn and Girl Scout cookies. The group includes dimwitted Hammy, sexy skunk Stella (Wanda Sykes), shellshocked turtle Verne (Shandling) and two melodramatic possums (Shatner and Lavigne). Their mission is led by R.J. Raccoon, a charismatic scavenger with a shady past.

"I start out cool," Willis said of R.J., "but I end up becoming the loneliest, doesn't-have-any-friends [guy], and I find out it's just a lonely husk of what I've convinced myself [I am]. He finds out that he needs family and he needs friends. So it's a cool little moralistic tale about how important family is."

The actors worked together to enter the cartoon world, much like the way their characters lean on each other as they enter the world of the humans.

"It's such a process," Lavigne said of her first animated film, which also happens to be her first film, period. "The first time [I saw Heather the possum], it was like just a sketch. It was barely moving when they played it for me, and then finally I got to see the end results. It looks really cool."

"A steamroller can run you over, and you can pick yourself right back up," Willis said of what he likes best about being animated. "Shake yourself out, and you're right back to life. ... You can be blown up by 10 tons of TNT and you're OK. You just have a little smoke coming out of your ears."

"Boy, there are just so many perks," Carell said of life as a cartoon. "You get the red-carpet treatment everywhere you go. Then there are the dolls: I went to a toy store with my daughter a couple of weeks ago, and there was a little Hammy in some sort of snow globe. Hammy moved and snow swirled around him, and for the life of me I couldn't understand why. But I had to buy it. ... My daughter immediately recognized my voice."

As recent cartoon disappointments like "Sinbad" and "Doogal" have shown, simply casting big names as animated voices isn't enough to make a movie work. When directors Tim Johnson ("Antz") and Karey Kirkpatrick (writer of "Chicken Run") set out to bring the long-running "Over the Hedge" comic strip to life, they considered vocal range first and star wattage second.

"We listened to interviews of Avril on 'Total Request Live,' " Kirkpatrick said of the Lavigne casting.

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"It's easy to hear her sing, but she doesn't do a lot of interviews," Johnson added. "We listened to an interview with her, and she has a little Toronto curve to her voice, so it doesn't sound like every Southern California actress you've ever heard. The thing that makes her music great is what makes her voice great: There's a toughness to it, and there's something that says, 'I'm smart; don't underestimate me.' "

Soon enough, Lavigne was learning from an actor made legendary by his knack for over-the-top dramatic moments. "What [Shatner] does is he fearlessly goes -- I'm not going to say 'Where no man has gone before,' " laughed Kirkpatrick. "[He said,] 'I'm going to hit 11 until you tell me that 11 is too big,' and he does it with such gusto and such commitment that you buy it. When we conceived this character, we thought we were going to have a possum, and what's going to be fun about him is he's going to die like a Shakespearean actor."

"Avril Lavigne's voice is heaven as a 16-year-old possum daughter of this extravagant Shakespearean," laughed Johnson. "She dies a little bit of embarrassment whenever he dies."

Carell said "Over the Hedge" breaks barriers in the typically kid-targeted world of animation.

"If there is an envelope to be pushed in a kid's movie, I think they do it, but without crossing any line," Carell said of the film's occasional adult joke. "It's as edgy as a movie like this would get, I believe. And there's a nice story too. There's a nice moral behind it, without being too preachy."

So if you ever do spot any scavenging animals in your trash, you might not want to kill them -- after all, they might just be trying to teach you a moral lesson. And, as Carell insisted, it would be cruel to kill any animal as deliriously stupid as the nut-hungry nut job he portrays.

"I revel in my stupidity," the "Anchorman" star confessed. "A lot of people say it takes somebody of great intelligence to play dumb well, but I think it's just the opposite. I think the more stupid you are, the better you can play dumb."

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