Former Spice Girl Geri Halliwell opened the Model United Nations Millennium Summit today for more than 100 students from across Europe who will spend the next two days debating global issues.
The onetime Ginger Spice, who is also a Goodwill Ambassador for the U.N. Population Fund, told about 120 teenagers that they had the power to change the world.
"Your minds are sharp and objective. You don't have cynical attitudes," Geri said at the International Maritime Organization in London, where the conference was being held.
"Your dreams and ideas are fresh and innovative - sitting in this room there may be another Einstein, Mozart or Madonna, or a future Prime Minister."
"All of you have the power to inspire or even change the world, and I mean that," she added.
Geri, dressed in a pale grey trouser suit, also spoke to the teens candidly about safe sex, which is one of the topics she has been asked to focus on in her U.N. role.
"It's my job to raise awareness about the need to improve sexual reproductive health," she said, calling for every person in the world to receive sex education.
"So, let's talk about sex ... because the trouble is we don't talk about it enough - not in the right sort of way. We either find sex embarrassing or we think we know it all. Maybe you do, but I know I certainly don't."
"But, like most things, it has its consequences," Geri added, "and it's those consequences that everyone has a right to know about."
She also hinted about she had felt pressurised to lose her virginity as a teenager: "I think puberty is really hard, and dealing with the peer pressure to become sexually active is even harder.
"I remember the massive pressure to lose one's virginity - everyone else seemed to have done it."
She was heckled by anti-abortion protesters as she stepped out of a silver Mercedes to walk into the International Maritime Organisation Headquarters, where the conference was held.
At one point her speech was interrupted by two women claiming to be from Latin America, who called her "phoney" and said Marie Stopes was interfering with their country.
They were herded out by security men.
Halliwell, who had been telling the teenagers their ideas were "fresh and innovative" said: "Everyone's allowed to have their opinion.
"I applaud that - that's a real example of that."
Throughout the summit, the students will debate poverty reduction, education, AIDS, crime and drug abuse and violence, including the use of children in armed conflicts.
At the conclusion of the two day conference, the teens will produce a declaration setting out what U.N. action they would like to see in the new century. The declaration will be presented to the United Nations in September. Geri urged the teens to consider asking for a permanent representative to the global body.