Affleck teamed with Mick Jagger and the United Nations to release a short film, Gimme Shelter, in 2009, which focused on the plight of displaced Congolese refugees. In 2010, he established the Eastern Congo Initiative, which provides aid and grants to the war-ravaged region. In 2012, the organization partnered with Theo Chocolate to make chocolate bars entirely from Congolese cocoa. Proceeds from the sales go to the ECI to help local farmers.

White's name is as synonymous with animals as it is with comedy. The lifelong advocate — she claims she's loved animals since she was in the womb — works with the ASPCA, the Los Angeles Zoo and the Morris Animal Foundation, on which she serves as president emeritus. But she doesn't like being called an activist. "I don't get into the political side or the demonstrative side," she told TVGuide.com in 2009. "I'm just totally devoted to health and welfare."

The U2 singer is involved with a number of different charities and regularly meets with leaders around the globe to speak out about issues ranging from HIV/AIDS to third world poverty. He was named the most politically effective celebrity of all time by the National Journal in 2011 and has been nominated for the Nobel Peace Prize three times. Bono also is the founder of the ONE Foundation, which fights extreme poverty and preventable disease, particularly in Africa; and Product Red, which has partnered with companies like Apple and Gap to raise funds and awareness to combat HIV and AIDS in Africa.

Brangelina has been the face of celebrity philanthropy the past decade. As special envoy and goodwill ambassador for the Untied Nationals High Commissioner for Refugees, Jolie has traveled to more than 30 countries for humanitarian causes, including Darfur, Sierra Leone, Tanzania, Pakistan, Chad, Afghanistan and Libya. In 2006, Pitt founded the Make It Right Foundation, which is dedicated to rebuilding the couple's adopted home of New Orleans in the wake of Hurricane Katrina. Together, the pair established the Jolie-Pitt Foundation, aimed at supporting humanitarian causes worldwide.

The Gary Sinise Foundation, founded in 2010, provides services for military servicemen and women, veterans, first responders, and their families. These include job training and placement, home-building, and counseling. Sinise himself has also traveled around the world visiting U.S. troops and their families. The actor is also the co-founder of Operation International Children, which collects school supplies, sports equipment and other materials, and sends them to kids in conflict areas overseas. The organization also sent goods to New Orleans after Hurricane Katrina and to Haiti after the 2010 earthquake.

Clooney is involved with various charity causes, but he is primarily known for his work to resolve the conflict in Darfur. He has filmed a documentary and spoken at several political rallies about the cause, even going as far as getting arrested for civil disobedience in March 2012 during a demonstration outside the Sudanese Embassy in Washington, D.C. Clooney is also a member of the Not On Our Watch program, which works to prevent mass atrocities. In 2010, he organized a telethon to raise money for victims of the earthquake in Haiti, and in 2008, he was named a UN Messenger of Peace.

The Star Wars director founded the George Lucas Educational Foundation under the brand Edutopia, a nonprofit that encourages innovation in schools. Lucas, who also supports the Film Foundation, Stand Up to Cancer and the Make-A-Wish Foundation, has donated $175-180 million to his alma mater USC, and in November 2012, after Disney acquired Lucasfilm for $4 billion, the director said the money would go toward funding education. Lucas is one of many people who've signed Bill Gates and Warren Buffett's The Giving Pledge, which encourages wealthy Americans to donate their money to charities.

After getting engaged to longtime boyfriend Justin Mikita in September 2012, the Modern Family star launched a bowtie line called Tie the Knot, the proceeds of which will benefit gay rights charities. "We're just like millions of Americans who are denied the basic civil rights to marry the person that we love," Ferguson said in a video clip announcing the project.

Gaga has staunchly supported and donated money to numerous causes, from disaster relief (Haiti earthquake, Japan tsunami), to HIV and AIDS (her cosmetic line Viva Glam has raised more than $202 million to fight the diseases), animal rights (remember that meat dress?) and perhaps most famously, equal rights. A gay icon, Gaga has been outspoken for LGBT rights, vociferously calling for the overturn of "Don't Ask, Don't Tell" and often speaking and performing at rallies. In 2011, the singer co-founded the Born This Way Foundation with her mother at Harvard to empower youths.

In 2006, Madonna co-founded Raising Malawi, a nonprofit that provides food, clothing, shelter, education, medical care and other resources to orphans and vulnerable children in Malawi, the birthplace of the Queen of Pop's son David and daughter Mercy. The charity also offers scholarships for girls to attend secondary school and has broken ground on 10 schools in Malawi, all of which are expected to be completed in 2013.

The retired NBA player was one of the first public figures to announce that he was HIV-positive, doing so in 1991, when he was still an active player. After going public with his diagnosis, Johnson founded the Magic Johnson Foundation to help fight the spread of the disease and reduce the stigmas associated with it. In addition to advocating for federal funding in the fight against AIDS, Johnson has also spoken at the United Nations World AIDS Day Conference and has served as a United Nations Messenger of Peace.

Damon is the co-founder of Water.org, a nonprofit aimed at providing safe drinking water for developing countries that do not have access to any. He also established the Not On Our Watch Project with Ocean's 11 co-stars George Clooney, Brad Pitt and Don Cheadle to raise awareness about and to stop mass atrocities in such places as Darfur.

McConaughey started the just keep livin (j.k. livin) foundation with his wife Camila to encourage high school students to live more active, healthier lives. The organization has implemented after-school programs in schools around the country to promote mental and physical wellness among students. The actor's philanthropic efforts also extend to animal rights — he rescued a number of abandoned or stranded pets after Hurricane Katrina.

The Oscar-winning actress and her husband Don Gummer have quietly given away millions of dollars over the years to schools and various philanthropic causes through the Silver Mountain Arts Foundation, which they founded. Streep is also the spokesperson for the National Women's History Museum and has done work for Broadway Cares/Equity Fights AIDS, Stand Up to Cancer and several other charitable organizations.

Fox, who was diagnosed with Parkinson's disease in 1991, founded the Michael J. Fox Foundation for Parkinson's Research, a charity that promotes awareness of the disease and whose proceeds go toward research to find a cure for it. Since going public with his diagnosis in 1998, the actor has also been an outspoken advocate for stem cell research and has received three honorary doctorate degrees for his activism.

The talk-show queen became the first black person to rank among BusinessWeek's Top 50 Most Generous Americans in 2004 and founded The Angel Network, which until its dissolution in 2010, provided grants to nonprofits. The Angel Network also raised more than $11 million for Hurricane Katrina relief efforts and Winfrey personally donated $10 million of her own money. In 2007, she opened Oprah Winfrey Leadership Academy for Girls in Johannesburg, South Africa, to help girls with impoverished backgrounds in the country.

A long supporter of the Red Cross, Bullock has donated $1 million to the organization at least four times that has been revealed publicly, including for the Haiti and Japan relief efforts. The Oscar winner has also donated money to various schools in New Orleans, the birthplace of her son Louis. In 2012, she was inducted into the Warren Eason Charter High School &mdash which was destroyed by Hurricane Katrina — for her charitable contributions.

Penn, who infamously denounced the Bush administration in an open letter in 2002, has long been involved in social causes, but he's most well-known for his recent efforts in earthquake-ravaged Haiti. The two-time Oscar winner founded the J/P Haitian Relief Organization with Bosnian philanthropist Sanela Diana Jenkins, focused on recovery efforts, and manages a 55,000-person tent camp for displaced citizens. In January 2012, Penn, who has said he'll be in Haiti "for the long haul," was designated Ambassador-at-Large for Haiti, the first time that a non-Haitian citizen has received the honor.

The Smiths have been involved with a number of philanthropic efforts, including founding the Will and Jada Smith Family Foundation, which fosters community development in inner cities, and also benefits youth educational projects and underprivileged children and their families. The couple have also partnered with the charity: water project, which raises funds to bring clean drinking water to third world countries, and have additionally been major players in the fight against human trafficking.