Angelina Jolie

Actress Angelina Jolie listens to remarks on Capitol Hill, on November 17, 2005. (REUTERS)

Nicole Kidman

Actress Nicole Kidman testifies on international violence against women before the House Foreign Affairs committee on Capitol Hill, on October 21, 2009. (REUTERS)

Eva Longoria

Actress Eva Longoria Parker speaks to the media among U.S. lawmakrers in front of the U.S. Capitol, on October 13, 2009. (REUTERS)

Jennifer Lopez and Marc Anthony

Actress Jennifer Lopez and her husband singer Marc Anthony arrive at a meeting with Speaker of the House Nancy Pelosi to discuss education in the Latino community on Capitol Hill, on September 16, 2009. (REUTERS)

Usher

Usher smiles as he testifies to the House Education and Labor Committee on "Improving America's Commitment to Service and Volunteerism," on Capitol Hill, on February 25, 2009. (REUTERS)

Sheryl Crow

Singer Sheryl Crow testifies before the House subcommittee on health about breast cancer research and patient legislation on Capitol Hill, on May 21, 2008. (REUTERS)

Richard Gere

Actor and pro-Tibet activist Richard Gere is greeted by Senator Barbara Boxer before testifying to the Senate Foreign Relations East Asian and Pacific Affairs Subcommittee on the situation in Tibet on Capitol Hill, April 23, 2008. (REUTERS)

Pamela Anderson

Actress Pamela Anderson stops to talk to Capitol Hill police as she arrives at the Department of Health and Human Services to deliver a People for the Ethical Treatment of Animals (PETA) report on outdated animal tests performed by the U.S. government, on April 25, 2008. (REUTERS)

Shakira

Singer Shakira speaks about the Global Campaign for Education on Capitol Hill, on April 22, 2008. (REUTERS)

Bono

U2 lead singer Bono arrives to meet the Senate Foreign Relations Committee on Capitol Hill, on October 3, 2007. (REUTERS)

Elton John

Sir Elton John waits to testify before his appearance in front of the Senate Committee on Health, Education, Labor and Pensions about increased funding for the global battle against the AIDS virus, on Capitol Hill, on April 11, 2002. (REUTERS)

Salma Hayek

Actress Salma Hayek speaks on violence against women at a hearing held by the Senate Committee on the Judiciary on Capitol Hill, on July 19, 2005. (REUTERS)

George Clooney

Actor George Clooney speaks at a rally calling for a stop to the genocide taking place in Darfur, in front of Capitol Hill, on April 30, 2006. (REUTERS)