UNITED NATIONS (AFP) ― The United Nations is throwing a party on Friday for its 69th birthday and guests can expect to be dazzled by Sting and piano sensation Lang Lang at a New York concert hosted by Alec Baldwin. 

Secretary-General Ban Ki-moon will be hand, as will Sam Kutesa, president of the General Assembly, but getting the world to notice the work of the United Nations these days requires more than savvy diplomacy.

A long list of celebrities are shining a spotlight on just about everything that the global body does, from fighting Ebola to the struggle against stunting ― a condition caused by malnutrition in which children fail to grow.

The campaign against stunting just got a boost from Indian mega-star Aamir Khan, who put his star power to work for the U.N. children’s agency UNICEF as an ambassador in South Asia with special focus on the condition, which affects nearly four out of 10 children in the region.

Two weeks ago, it was David Beckham’s turn to appear in a UNICEF video to encourage people in Ebola-hit Sierra Leone to seek medical help and to make a pitch for donations.

But the U.N.’s biggest publicity coup came at the U.N. climate summit last month when Leonardo DiCaprio turned up in a ponytail and suit to deliver his appeal to save the planet.

The video of DiCaprio’s speech has been watched by more than 1.5 million viewers ― an all-time record for a U.N. video ― while his tweets, and retweets, from the summit reached his 11.3 million followers.

By contrast, the United Nations Twitter account has a mere 3.3 million followers.

“Sometimes an issue is not on a map until a celebrity puts it on a map,” said Maher Nasser, the head of the U.N.’s public information department.

“You are talking about amplifying and giving access to people who become interested in an issue because it’s their celebrity of choice.”

U.N. officials approached DiCaprio two years ago to discuss a linkup with the climate campaign and his appointment as a U.N. messenger of peace was announced just ahead of the summit to maximize impact, said Nasser.

The star of “The Wolf of Wall Street” and “Titanic” has been active on the climate front through his foundation and U.N. officials say they were impressed by his knowledge of the issues.

Critics however say stars who endorse U.N. campaigns are self-serving, seeking to cultivate an image as caring individuals and global citizens ― far removed from the vacuous world of superstardom.

For the United Nations, the challenge has been to pick celebrities that have a track record of engagement and can speak with some authority to avoid cheapening the U.N. brand.

The U.N. refugee agency, UNHCR, scored success when it took Lebanese-born singer Maher Zain ― and his massive global digital fan base of 22 million Facebook followers ― on a recent trip to his home country to meet Syrian refugees.

Over a month, Maher’s social media remained the third biggest driver of traffic to UNHCR’s website, said Claire Lewis, a private consultant who finds “high-level supporters” for charities including the U.N..

“The public and the media can be cynical about relationships between NGOs and celebrities that can look self-serving and PR hungry, and you need to find a balance where the people you work with have a genuine and often personal commitment to the issue,” said Lewis.

Few celebrities have done more to raise the profile of a U.N. agency than Angelina Jolie, who was named UNHCR goodwill ambassador in 2001 and special envoy in 2012.

“She still creates for UNHCR their greatest source of web hits,” said Lewis.

The first celebrity to bring glamor to the U.N. was actor Danny Kaye, who was named UNICEF goodwill ambassador in 1954 to boost the agency’s recognition.