(CNN) -- The holidays are a time of reflection and often a time of charity, even for some of Hollywood's biggest stars.
CNN's Alina Cho is taking a special look at how three celebrities are doing their part for causes near to their hearts in this year's "Big Stars, Big Giving," which is scheduled to air 8 a.m., 10 a.m. and 2 p.m. ET December 26-28 on CNN.
Academy Award winner Matt Damon is using his star power to lead the way for change and bring clean water to those who do not have access to such a basic staple.
"Every 20 seconds, a kid under the age of 5 is dying, losing their life because they do not have access to clean water. And it just doesn't have to be that way," Damon tells CNN.
Damon and water expert Gary White founded water.org in 2009 with a plan for what Damon says is a solvable problem. Close to a billion people do not have an affordable solution to clean drinking water, and the problem is twofold.
"To me, the most disturbing thing, not only is it contaminated, but people are walking hours to get this kind of water, " Damon said in an interview with Impact Your World a few years ago, "So, you're forced to give your children this water knowing that the chances of them getting a water-borne disease is pretty high."
Damon and White say that charity is not enough and have created the concept of "water credit," which allows people access to affordable loans to buy a toilet or a faucet to bring clean running water into their homes. And it's working. White says that loans are being paid back at a rate of 98% in places such as Haiti.
Actor Matthew McConaughey and his wife, Camila, have made bettering the lives of young adults their mission. They founded the Just Keep Livin, or the J.K. Livin Foundation, to empower high school students "to lead active lives and make healthy choices to become great men and women," as their mission states.
"I want to find a place where I can help out where it's prevention before you need a cure," McConaughey tells CNN.
McConaughey has so far brought the J.K. Livin Foundation into 14 schools without after-school programs and where 75% of the students are on a free or reduced lunch program and below the poverty line.
They are students who come from families who might not have the means to provide healthy meals or access to gyms. The J.K. Livin Foundation gives the students a safe place to be after school and the tools they need to grow into healthy adults. The program meets twice a week for two hours a day and is voluntary. The students who choose to attend participate in physical fitness, nutrition education and a gratitude circle.
"Everyone goes around and says something that they are thankful for. And that's a lesson that came from my mother and the family I grew up in. I found that the more you find something to be thankful for, the more you end up having things to be thankful for, and so it goes well beyond the gym," says McConaughey.
In addition to establishing herself as one of Hollywood's leading ladies, Eva Longoria has also made a name for herself campaigning for social issues. She's lent her voice to raise awareness of the AIDS crisis in Africa and sex trafficking in Thailand. When she decided she wanted to create her own foundation in 2010, she decided on a cause that hit much closer to home for her. The Eva Longoria Foundation aims to help Hispanic women get a college education.
Some 27% of Latinas live below the poverty line, and 17% drop out of high school. Only 15% of adult Latinas have college degrees. Longoria hopes to empower women and change those statistics.
"I come from a family of teachers. I wasn't the first to go to college. It was expected, and that's rare in a lot of low-income families and a lot of minority families," says Longoria.
Longoria's foundation supports other programs that help Hispanic women excel in their education, and it aims to provide Latina entrepreneurs with career training, mentorship, capital and opportunity.
"I don't want the Latino community to just be a large community. We need to be an educated community because this is going to be our future work force," says Longoria.