"There is an extraordinary, compelling, urgent problem," she said, noting that more than 12 million people under the age of 25 are infected with HIV and that more than 50 percent of all new infections occur among 15- to 24-year-olds.

For Judd, YouthAIDS founder Kate Roberts is a hero because "she has a very clear vision ... which is a world free of HIV."

Roberts never intended to become an activist. Living in Moscow and Eastern Europe in the 1990s, the British-born woman lived life in the fast lane. She dated a rock star. She wore designer clothes.