WATCH: Charlie Sheen Comes Out as HIV-Positive

Actor Charlie Sheen appeared on NBC's Today show Tuesday to tell the world that he is HIV-positive. He was motivated, he said, by a desire to stop extortion efforts by those who threatened to disclose his status.

Sheen said he had paid $10 million to people threatening to out him. "I think I release myself from this prison today," he said regarding extortion efforts. One's HIV status is personally protected medical information, yet the condition is so stigmatized that outing someone is still a viable threat.

Though the virus is treatable with modern medicine, knowingly spreading HIV without disclosing one's positive status is still considered a crime in many states.

When one comes out as Sheen did, past sexual partners may be scrutinized for signs of HIV in what seems like a modern day witchhunt. In the interview, anchor Matt Lauer asked Sheen about his former wives, indicating that Sheen had been with one of them around the time of his diagnosis.

In a letter to Lauer, Sheen wrote that his diagnosis led to a downward spiral of shame, anger and substance abuse, but on the show he said he no longer feels shame for having HIV.

"I have a responsibility now to better myself and to help a lot of other people and hopefully with what we're doing today others will come forward and say, 'thanks Charlie,'" Sheen said.

Answering a number of highly personal questions, the actor told Lauer that he didn't know how he contracted HIV four years ago, but insisted he hadn't knowingly or unknowingly infected anyone else with the virus. "Impossible," he told Lauer. Sheen said he engaged in unprotected sex with two people since his diagnosis, but he said both were informed ahead of time of his status and were under the care of his doctor, who also appeared on the show.

By regularly taking medication, Sheen's doctor, Robert Huizenga, said the actor has managed to control his viral load. The doctor said his biggest concern for Sheen was his depression and substance abuse.

"We're so, so anxious that if he was overly depressed, if he was abusing substance, he would forget these pills and that's been an incredible worry," Huizenga said. However, "Magically, somehow in the midst of incredible personal mayhem, he's managed to continue to take these medications."

Lauer asked Sheen if he fears being charged criminally, explaining that having sex with someone without disclosing one's HIV status could result in criminal charges in 35 states. "Having divulged, it is the reason I am in the mess that I am in with having all the shakedowns," Sheen said. HIV remains one of the most stigmatized conditions in America.

Watch Matt Lauer's interview with Charlie Sheen on the Today show, below.