Naomi Watts, the Oscar-nominated actress who starred in King Kong and Mulholland Drive, was named on Monday as a special United Nations envoy on HIV/ AIDS.
UNAIDS said that in the role, Watts would "use her talent and profile to raise AIDS awareness and give greater voice to the needs of people living with HIV worldwide."
The 37-year-old, born in Britain and raised in Australia, recently joined a UNAIDS mission to Zambia where she visited clinics, hospitals, schools and shelters.
Watts said she was "humbled and inspired" by those she met.
"I only hope that, as a UNAIDS Special Representative, I can do my small part to raise AIDS awareness and to encourage greater international support for the vital work being done on the ground," she said in a statement.
About 40 million people worldwide are infected with HIV, the virus that leads to AIDS. Most sufferers live in Africa where AIDS is the leading cause of death.