HOLLYWOOD - As a mother of two, Joan Cusack didn't need to research her role for the new Disney animated action-adventure "Mars Needs Moms." She could delve into her own experience as a caring, nurturing and, yes, sometimes nagging adult.

"It's a thing primordial," the comedic actress says of parenthood. "It's a thing that's timeless about life. They've existed forever and they'll continue to exist forever. As long as there are humans, there will be mothers and fathers and children. And you'll either be a parent or a child, or both."

Cusack plays - what else? - a mom who is kidnapped by Martians and brought to the Red Planet where her memories are targeted for extraction so they can be used to foster Martian babies. Somewhere along the way, the female-dominant society forgot how to be moms, so they created robots to perform the task. The robots need help on the nurturing aspect, though.

Every 25 years or so, the Martians target a mom from Earth - the best they can find - and steal her memories to raise the planet's girls. A matriarchal society, led by a totalitarian leader known simply as the Supervisor (Mindy Sterling, of "Austin Powers"), Mars has plenty of women, but no moms. After hatching, the girls are raised in a militaristic society by the 'bots while the boys are banished to a junkyardlike subterranean level where previously discarded older males raise them.

Little do the alien kidnappers realize a 9-year-old stowaway has climbed aboard their spaceship, with the intention of rescuing his mom. Milo (Seth Green, also of "Austin Powers") has little time to accomplish his mission before his mom's memories are taken and her body discarded. He gets some help from another stranded earthling (Dan Fogler, of "Take Me Home Tonight") and a rebel soldier (Elisabeth Harnois, of "Miami Medical").

The PG-rated animated action-adventure is based on the illustrated book by cartoonist Berkeley Breathed. (Breathed is also the creator of the Pulitzer Prize-winning "Bloom County.")

Director Simon Wells ("The Time Machine," "Prince of Egypt"), who wrote the adapted screenplay with his wife, Wendy, said he could think of no one better for the mom role than Cusack, a two-time Oscar nominee ("Working Girl," "In & Out"). Over the years, Cusack has played a number of moms.

"We just sort of thought what mom-age actors are out there and Joan was our first choice," the British filmmaker says. "We contacted her and it turns out she has a son named Miles who's exactly the same age as Milo. So it was meant to be."

The Milo-Miles coincidence could get a little confusing. Sometimes Cusack found herself saying "Miles" instead of "Milo" during production, and would have to repeat her lines.

The veteran actress is quite familiar with voiceover for animated movies. Most notably, she was Jessie the yodeling cowgirl doll in the two "Toy Story" sequels, as well as a duck in "Chicken Little."

As a mom who wants to be home as much as possible without sacrificing her career, Cusack appreciates the advantages of doing voiceover work. She doesn't have to be away from home on location as long as is typically required on a live-action movie, and she doesn't have to worry about her appearance. She and her husband, a lawyer, live in Chicago with sons Miles and Dylan.

"Mars Needs Moms" required more than simply Cusack's distinctive Midwestern drawl, though. It needed a physical performance, too. Like "The Polar Express" (which featured Oscar winner Tom Hanks in multiple roles) and "A Christmas Carol" (which featured Jim Carrey in multiple roles), "Mars Needs Moms" utilizes motion-capture technology to animate the characters. That meant during production Cusack and her co-stars had to wear bodysuits specially equipped with sensors, and perform the action on a stark white stage as they were filmed. They were digitally converted into remarkably lifelike animated characters and inserted into the alien world concocted by the filmmakers.

"It was so fascinating - what they do and how they do it," the actress marvels. "It's a lot like doing improvisational theater."

The work was fast and intense, but took about half the time of a shooting for a regular live-action movie.

The 48-year-old actress enjoyed the simple preparation process.

"I'm not huge on the hair, makeup and wardrobe stuff," she says, "even though it's fun sometimes, like when you do a period piece. To me it was so great not to have to think about that stuff. And worry about what you're eating for lunch. I got to do just the acting part. I was just grateful."

Performing on an empty stage and imagining her surroundings reminded Cusack of her early days of acting with an improv troupe.

It was a little tricky, though, getting into a harness and being swung around a soundstage for one scene (to simulate leaping across the terrain of Mars' low-gravity atmosphere).

As the mom, Cusack's character is willing to make the ultimate sacrifice for her boy while her son learns to appreciate his mom, even though she always nags him about doing chores and eating broccoli.

Cusack liked the movie's positive message and how it depicted parenthood.

"It's harder to not be your kid's friend but it's more important," she says, smiling.

"It's another level of love that's hard to understand. If you're just their friend you wouldn't care as much as you do because you care at such a big level about your kids. You want to help shape them so you're thinking about all aspects of them. A friend is really just a smaller relationship than what a mom really wants to do."

Cusack watched "Mars Needs Moms" with her sons and says they were really moved by the story. Cusack plays an entirely different sort of character in the hit Showtime series, "Shameless." She is sure that the edgy comedy series, in which she plays an agoraphobic seductress, is something her children won't be seeing anytime soon.

"They know about it and about some of the stuff that's been in it," she says, blaming the Internet for revealing more than she'd like for them to know. "We've had some really frank conversations where I've given truly Oscar-worthy performances of keeping a straight face when I was shocked and horrified about what they knew about."