“Alyssa Milano couldn’t contain her tears Tuesday discussing former “Who’s the Boss?” costar Daniel Pintauro’s recently revealed HIV-positive status on “The Talk.”

“I hate that it took him so long to feel comfortable, but I’m so glad that he is able to express himself now,” the “Mistresses” actress said of her fellow child actor.

Pintauro, 39, revealed Saturday on “Oprah: Where Are They Now?” that he’s been HIV-positive for 12 years, following a post-relationship period in which he was experimenting with sex while using crystal meth. He said he knew exactly when he contracted the virus, and that he “didn’t want to be that guy” for anyone else.

“There’s this awful feeling of, I’m never going to be able to have a good relationship,” he told Oprah Winfrey, discussing his reaction to the news in March 2003. “No one’s ever going to want me.’ … That moment of, ‘Oh, God, I’m now going to have to have that conversation every time I meet someone. Who’s going to want to love me?'”

Pintauro, who was forced to come out about his sexuality in 1997 after a tabloid told him it was going to out him whether he participated or not, now wants to be an activist about HIV and the dangers of crystal meth.

“I guarantee you he will change so many lives,” Milano said Tuesday. “And I’m so grateful that this disease is now being discussed again because it feels like there was such a long time that it wasn’t.”

Echoing some of Pintauro’s words from the Oprah sit-down, she declared, “He is a beacon of light, and he will be.”

She said she had “no idea” that her former costar was HIV-positive, because she’d fallen out of contact with him since their show wrapped in 1992 after eight seasons.

“Danny and I didn’t talk for many years after the show was over, because when the show ended it was a different time. We didn’t have cellphones or Facebook or anything,” she said. “I would’ve been calling his parents’ house, being like, ‘Can I talk to Danny?'””