Eliza Dushku

How do you bring together, for the first time, four of TV’s hottest new stars? Give them a chance to talk about this week’s hottest topic: volunteering.

Starting Monday, four major broadcast networks — ABC, CBS, NBC and Fox — will slip messages about service into more than 60 of your favorite shows: dramas, comedies and reality alike. It’s the centerpiece of I Participate, a multiyear effort to encourage Americans to volunteer led by the Entertainment Industry Foundation — Hollywood’s leading charity.

Millions will turn this TV inspiration into real-life action next Saturday on Make A Difference Day. For nearly two decades, on the fourth Saturday of October, USA WEEKEND’s Make A Difference Day has inspired millions worldwide to feed, clothe, house, teach and soothe their neighbors.

"There’s strength in numbers," says actress Eliza Dushku, star of Fox’s Dollhouse. "People can band together on Make A Difference Day and say ’together we can.’ " She’s one of four stars who gathered in Los Angeles to represent their shows, their networks and their own commitment to helping others. Joining her: Nathan Fillion of ABC’s

"Castle," Hayden Panettiere of NBC’s "Heroes" and Hill Harper of "CSI: NY" on CBS. "There’s strength in numbers. People can band together on Make A Difference Day and say ’together we can.’"

— Eliza Dushku of Fox’s "Dollhouse," who aids former child soldiers in Africa

Dushku, 28, is just back from Uganda, where she met with the founder of THARCE-Gulu, a trauma healing and reflection center for former child soldiers. She used Twitter to spread the word about what she was doing there, hoping to get others to help, too.

That embodies the simple, powerful idea behind I Participate and Make A Difference Day: Studies show that nearly half of all people who volunteer started because they were asked to by someone they know.

"If you can teach a kid to read, he can do anything."

— Nathan Fillion of ABC’s "Castle," who is the co-founder of a children’s literacy group

Fillion, 38, responded when he co-founded his charity, Kids Need to Read, with good friend and children’s book author PJ Haarsma. "I’d never been a volunteer, but if you turn to a friend and say, ’This is what I’m going to do, and I want you to join me,’ it’s fantastic," Fillion says. As the son of two English teachers, he knows one of the best ways to help kids is to give them access to books: "If you can teach a kid to read, he can do anything."

"When you have passion [for your volunteer work], you’re not so easily deterred."

— Hayden Panettiere of NBC’s "Heroes," who fights for animal rights

It was a co-worker who invited Panettiere, 20, to volunteer. She was 15 and filming "Shanghai Kiss;" crew member Jeff Pantukhoff, founder of the Whaleman Foundation, showed her footage of whales and dolphins and asked her to get involved. Since then, she has been on the front lines, trying to save them from slaughter.

Her advice is to find a cause you’re passionate about: "When you have passion, you’re not so easily deterred."

"One day will multiply into many days because people will discover that volunteering is addictive."

— Hill Harper of CBS’ CSI: NY, who helps underserved youth

Harper, 43, learned by example. One set of grandparents took in needy strangers. Another grandparent ran a pharmacy — one of the only places in segregated South Carolina where blacks could fill prescriptions. "I’d see him trade prescription products for sacks of potatoes or just give them away. He really served the community," he says.

Harper’s service began when he was a student at Brown University and continued as he studied government and law at Harvard (President Obama was one of his classmates). Now, his Manifest Your Destiny Foundation helps underserved youth.

Harper knows the high that comes with helping. "Make A Difference Day is fantastic," he says. "That one day will multiply into many days because so many people will discover that volunteering is addictive."