Former "Two and a Half Men" star Charlie Sheen has HIV.

In an interview Tuesday on NBC's "Today," the 50-year-old actor said he tested positive for the virus that causes AIDS about four years ago, but that, thanks to a rigorous drug regimen, he's healthy.

When asked by co-host Matt Lauer if he had transmitted the disease to others, he declared, "Impossible. Impossible," and insisted he had informed every sexual partner of his condition beforehand.

Since his diagnosis, he has had unprotected sex with only two partners, he said, adding, with no further clarification, "They were under the care of my doctor and they were completely warned ahead of time."

He said one reason for going public with his condition was to put a stop to shakedowns from prostitutes and others who threatened to out him. He said one prostitute took a photo of the HIV-related drugs in his medicine cabinet and threatened to sell that photo to the tabloids.

He said he had paid "enough to bring it into the millions" - perhaps as much as $10 million - to buy their silence and now was seeking to "put a stop to this barrage of attacks and sub-truths."

"Are you still paying these people?" Lauer asked him.

"Not after today I'm not," said Sheen, who during his appearance appeared jumpy and spoke in stuttering bursts.

He did not address when, and by whom, he may have been infected.

In the U.S., AIDS is spread mainly through having sex or sharing injection-drug equipment with someone who has HIV. About 1.2 million people in the U.S. are estimated to have HIV, with many of them unaware.

For part of the interview, Sheen was joined by his physician, Dr. Robert Huizenga, who said strong anti-viral drugs have suppressed the virus. The HIV level in Sheen's blood is "undetectable," Huizenga said, and flatly stated that he does not have AIDS.

"He is absolutely healthy," said Huizenga, adding that his own concern was for Sheen's "substance abuse and depression from the disease more than what the HIV virus could do to shorten his life, because it's not going to."

Sheen said in the past that he was "so depressed by the condition I was in that I was doing a lot of drugs, I was drinking way too much." He said he currently is not abusing drugs, though he allowed that he is "still drinking a little bit."

"My partying days are behind me," Sheen said in an "open letter" released by email. "My philanthropic days are ahead of me."

Asked by Lauer if he expected "a barrage of lawsuits" from past sexual partners alleging he infected them, he said wanly, "I'm sure that's next."

But in California, where Sheen resides, a person can be charged with a felony only if they are aware they are HIV-positive and engage in unprotected sex with another person with the specific intent of exposing them to the disease.

Sheen could potentially be sued in civil court by any partners he hasn't already settled with, with the amount of damages they would recoup determined by a judge or jury.

With his public pronouncement, Sheen said he hoped to reduce the stigma and shame still felt by some others diagnosed with HIV, as well as by those who are reluctant to be tested in the first place.

"I have a responsibility now to better myself and to help a lot of other people," he said. "And hopefully with what we're doing today, others may come forward and say, 'Thanks, Charlie, for kicking the door open.'" (Associated Press)

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