She slayed it in RuPaul’s Drag Race and Australian Idol and took home the crown in Celebrity Big Brother UK, but now reality TV superstar Courtney Act is getting real about HIV.

She stars in a video campaign to get the word out that “people living with HIV who are successfully treated do not pass HIV on to their sexual partners.” That’s the message of the “Ending HIV” campaign from the New Zealand AIDS Foundation.

In the video, titled “A Beginner’s Guide to Undetectable Viral Load (With Courtney Act),” which you can watch above, Courtney asks: “Did you know that someone living with HIV can have sex with HIV-negative people without the risk of passing it on?” before spelling out the science behind the fact that an undetectable viral load equals an untransmittable virus, or U=U.

What’s more, the upbeat message is nuanced and includes important caveats. “Even though everybody living with HIV in New Zealand has access to treatment,” she says, “not everyone can achieve an undetectable status, so it’s important not to put an expectation on someone to become undetectable.”

She also notes that for many folks, an undetectable status isn’t a replacement for condoms because only condoms offer protection against other sexually transmitted infections, such as gonorrhea and syphilis.

“An ex-boyfriend of mine is living with HIV,” Courtney said in a press release from the New Zealand AIDS Foundation. “He has an undetectable viral load, so I know firsthand how this can affect people in a serodiscordant couple—which is where one partner is HIV negative and one is HIV positive. It was great to know he could have much better health in the long run and that scientific evidence shows he was unable to pass on HIV to me, even without condoms. We live in a fear-based world where HIV stigma can prevail, but armed with science and fact, I was able to break down stigma in my own mind and be in a happy and healthy relationship with my partner.

“For people living with HIV, the knowledge that undetectable equals untransmittable is huge news, not only as a means of preventing transmission but in breaking down the stigma that many people still experience.”

For related stories in POZ, click #Undetectable, where you’ll find the CDC’s statement that there is “effectively no risk” of sexual transmission when undetectable.

UPDATE: Courtney’s quote about her ex-boyfriend resulted in some follow-up discussions about HIV and stigma. Click on her tweet above for more.