One of the biggest pop stars in America's revealing a family secret. Ryan lewis, who shot to the top of the music charts, alongside macklemore, is speaking out for the first time about his mother, who... See More
One of the biggest pop stars in America's revealing a family secret. Ryan lewis, who shot to the top of the music charts, alongside macklemore, is speaking out for the first time about his mother, who has been living with HIV for the past 30 years. ABC's Chris Connelly has that story for us. ♪ I can't say ♪ Reporter: With vocals by Mary lambert, macklemore and Ryan lewis' "Love" put them on the map. Now, Ryan lewis and his family are going global. Revealing that Ryan's mother, Julie lewis, has been hiv-positive, since giving birth to her firth child in 1984. My mom ended up needing a blood transfusion. And without anyone knowing it in that moment, that hiv-positive blood went into her body. At age 25, one year younger than I am right now, her life would change forever. Reporter: Undiagnosed, Julie would have two more children, laura and Ryan. Each at a 25% chance of being born with HIV. Neither was. I was diagnosed hiv-positive in the summer of 1990. I was 32 years old. And I had three, young children. They were 2, 4 and 6 years old. I had never thought about dying. But you know what's amazing? My mom never died. She lived. Reporter: In honor of her three decades for survival, timed to the 30th anniversary of the scientific discovery that AIDS is caused by the HIV virus, Ryan lewis and his mother have announced the 30/30 project. I want to do something big. Reporter: The lewises project seeks to build medical facilities in such places as Malawi, allowing people all over the world, to the same care that Julie received. 30/30 has macklemore's support. We want to see this idea put into action. What people need is to have -- I was infected with HIV 30 years ago. And I never thought I would be sitting here 30 years later, talking to you. Reporter: For "Good morning America," Chris Connelly, ABC news, New York. And joining us now with more on HIV and what Ryan lewis is doing to help, is our chief health and medical editor, Dr. Richard Besser. I know this is dear to your family's heart. When you look at the mother, and in 1984, wasn't diagnosed until six years later. Right. That's absolutely incredible. Most people, you go from HIV infection to AIDS to a death. But we do know, now, there's some people like this who slowly progress. And there's probably genetic differences that made her incredibly lucky. And lucky that Ryan and his sister, they had a 25% chance of contracting AIDS. What do we know about this mother-to-child? It's a critical period. If you diagnose a woman with HIV and you treat her during pregnancy and delivery, you cut that rate from 25% down to 1%. And you might -- there's programs around the world. My brother has one in Africa, mothers-to-mothers. And they find, if you can get the women to be tested, and that's a big hurdle for a lot of people, and give them that drug, you have a whole generation that don't have HIV. I remember being there with your brother. And the impact, you could see right there, the difference it was making. Yeah. You see the hope in people's eyes. The experience that Ryan and his sister have, is something that people around the globe are getting because of these kind of efforts. And speaking of impact, robin, how impactful is it that he steps forward and speaks out right now? Huge. Would we be talking about that today, here, if he hadn't had the courage to share his family's experience? Yeah. It shows a little bit of effort can make a big difference here and around the world. They're looking to raise $100,000. That's only one clinic. Yeah. They're working with partners in health. That's one of the best groups around the world for this kind of work. You can build a whole clinic for $100,000. Such a difference. It's incredible. We thank you so much.
This transcript has been automatically generated and may not be 100% accurate.