South African actress Charlize Theron threw her weight Tuesday behind an urgent new UN campaign to end AIDS as a global health threat by 2030.

The UN warned the HIV virus risks spiraling back out of control unless world leaders bolster action now by agreeing to "fast-track" efforts to eradicate AIDS.

A new UN report, launched by Theron and Michel Sidibe, executive director of UNAIDS, called for adoption of a set of medium-term targets to counter the disease, with the goal of preventing some 21 million AIDS-related deaths.

"We have bent the trajectory of the epidemic," said Sidibe. "Now we have five years to break it for good or risk the epidemic rebounding out of control."

The proposed strategy employs a "90-90-90" formula as the goal for 2020: 90 percent of people with HIV knowing their HIV status; 90 percent who know their HIV-positive status on treatment; and 90 percent of those on treatment with suppressed viral loads.

The number would then be stepped up to 95 by 2030, which if met would avert nearly 28 million new HIV infections, according to the study.

The fast-track strategy also aims to cut the annual number of new HIV infections by more than 75 percent to 500,000 in 2020 and then to 200,000 in 2030.

And it sets an additional target of zero discrimination against those with the virus by 2020.

- Responsibility 'to each other' -

Theron, a UN "messenger of peace" and head and founder of her own Africa Outreach Project, added: "When young people have access to quality HIV health and education options, they make smart choices for their futures.

"Let's make sure adolescents everywhere are empowered to be part of the solution to ending this epidemic," she said. "Meeting UNAIDS fast-track targets will ensure no one is left behind."

In an interview with AFP, Theron -- whose country has the most people living with HIV globally -- recalled how Britain's Princess Diana changed the way people talked about AIDS in the 1980s.

"A photograph of Princess Diana hugging and kissing an HIV positive patient in England," she said, "had a real effect on how people started talking truthfully about what HIV was."

She added: "By no means am I putting myself on the same level as Princess Diana, but I feel that we all have a responsibility to each other."

"Am I aware that I bring some kind of a spotlight to it? Sure. And I feel absolutely no shame to utilize that as much as I possibly can to get knowledge and access to this information across," she added.

Since 1981, around 78 million people have been infected by the human immunodeficiency virus (HIV) that causes AIDS, according to UNAIDS. Thirty-nine million have died from AIDS-related illnesses.

In 2013, around 35 million people were living with HIV, nearly 71 percent of them in sub-Saharan Africa.

Last year, 12.9 million people in low- and middle-income countries had access to HIV drugs, but at least 28 million are eligible for them under World Health Organization (WHO) guidelines.