Beyond the glamour of the red carpet and the clamor of fans at a rock concert, an elite group of celebrities have gotten so involved in diplomacy that they are eclipsing true diplomats.
"You know the Secretary General very often tells me, 'You know, whenever there is an opportunity we need a star.'…He says, 'Every time a star speaks, what I have to say just disappears, it has absolutely no meaning, no one listens to me, but people will listen to the star, will listen to the celebrity,' said U.N. spokesperson Michele Montas.
Nowadays these celebrities are taking on increasingly complex and weighty roles in the fights against poverty, pestilence and war.
U2's lead singer, Bono, has direct access to world leaders, and he's credited with bringing worldwide attention and money to the poverty and HIV crisis in Africa.
"I tell you what my Messianic complex is, I wanna have fun and I wanna change the world. That's it," he told ABC News Nightline anchor Cynthia McFadden.
Oscar winner Angelina Jolie recently traveled to Iraq for the second time and wrote an op-ed for the Washington Post about the refugee crisis there.
"Generals in Iraq, presidents of Iraq, they know if somebody like Angelina goes in they are going to be able to get the message across very quickly. And of course this is exactly what happens," said Andrew Cooper, author of the book "Celebrity Diplomacy" (Paradigm Publishers, 2007).
Jolie has even been invited to testify in front of the House Armed Services Committee and has teamed up with California Congresswoman Diane Feinstein to lobby for legislation on Iraqi refugee relief.
Jolie says her activism helps her counter the shallowness of Hollywood. "It gives celebrity some reason. Celebrity is very weird … So when you're doing something good, and you can bring attention to that, or discuss that, then it feels like you have some sense in your life," Jolie told ABC News "This Week" anchor George Stephanopoulos.
"Whether she was going to nightclubs and partying with Brad Pitt, there would be fleets of press following her, or taking them to the Chad border, a far more worthwhile endeavor," said actress Mia Farrow.
Farrow should know. She is a longtime UNICEF Goodwill Ambassador -- she's visited Darfur eight times on her own, and she's come back with stories of the slaughter in that region.
"I was given this [necklace] by a, a woman named Halima in 2004, a refugee. And she had been wearing it when her village was attacked. And she'd been holding her, her infant son. And, Arab militia tore her baby from her arms and bayoneted him before her eyes. ….They cut them and threw them into the well. And she clasped my hand and said, 'Tell people what is happening here. Tell them we will all be slaughtered. Tell them we need help," Farrow said.
She, along with her son Ronan, wrote an op-ed in the Wall Street Journal challenging Steven Spielberg's role as an artistic advisor for the Beijing Olympics, a position he later resigned.
"What she's done is shame the Chinese government to be involved in Darfur where there is a genocide going on … The Chinese take these embarrassments quite seriously," said Andrew Cooper.
Though Farrow has, for many years, been one of the most outspoken goodwill ambassadors, she has been joined in the ranks by many more major stars, such as Nicole Kidman, Whoopi Goldberg, Susan Sarandon, Shakira, Ricky Martin, tennis player Roger Federer, French actress Catherine Deneuve and Brazilian soccer player Ronaldo.
In January the United Nations named George Clooney a Messenger of Peace after he returned from a two week trip to Chad, the Congo and Darfur. "I think what they're looking to gain from it is cameras following me to places that they're trying to get attention to and that's fine. That's a good use of celebrity if you ask me," Clooney told ABC News' Tanya Rivera after the UN ceremony.
Other U.N. Messengers of Peace include Michael Douglas, Muhammad Ali and Magic Johnson.
This past week Drew Barrymore announced a $1 million donation to the United Nations World Food Program. Barrymore has been an Ambassador Against Hunger for the U.N. since last year, but the donation is by far her largest, and she hopes will draw attention to the rising global prices for food.
Some foreign policy analysts say that celebrities are far more likely to get involved in skirmishes and even ruffle some diplomatic feathers. Or, perhaps, they're also in it for the attention and up for the ground work.
Reese Witherspoon has teamed up with the UNIFEM, the United Nations Development Fund for Women, for projects that will empower women around the world. No doubt a good cause, Reese is helping the charity through her paid-role as a global ambassador for Avon, driving sales of Avon's Women's Empowerment bracelets, the proceeds of which go to Avon's Empowerment Fund, which collects money for UNIFEM.
When Farrow wrote on her website last year, "Jimmy Carter – Wake up, Jimmy! You're old enough to know better," the former president was offended. "Those are harsh words," he said in an interview with ABC News, responding to Farrow's comments about his own trip to Darfur and comments he made about a meeting with Sudanese President Oman al Bashir.
Farrow responded by saying, "I'm completely free to say anything I want. And you're right, I have no trade [LAUGHS] agreements with anyone and I can be as incautious as I, I feel the occasion calls for."
In his book "Celebrity Diplomacy," Andrew Cooper points out that Gerri "Ginger Spice" Halliwell, who was named a U.N. Goodwill Ambassador, may have had good intentions, but failed to follow through.
"The celebrities can attract attention on an issue, but they cannot solve a war. They cannot really be mediators in a crisis. There is no doubt that they have a limited role," said Montas -- a role best personified by pioneering star Audrey Hepburn who drew worldwide attention to UNICEF. Her legacy is one that today's stars hope to expand.