NEW YORK: Charlie Sheen, the wayward star of US television comedy “Two and A Half Men,” said on Tuesday he was diagnosed as HIV positive some four years ago and had been extorted for more than $10 million to keep the information quiet.

Sheen, 50, told NBC’s “Today” TV show he was speaking out because he was being blackmailed, and to refute tabloid reports that he has AIDS and was spreading it to others.

“I have to put a stop to this onslaught, this barrage of attacks and of subtruths and very harmful and mercurial stories,” he said.

“I am here to admit that I am in fact HIV positive,” Sheen said, adding he was “not entirely sure” how he contracted the virus.

Sheen acknowledged he had paid “upwards of $10 million” in recent years to “desperate charlatans” for their silence about his condition.

Sheen’s doctor, Robert Huizenga, said the actor “does not have AIDS,” that he is taking antiretroviral drugs and that his viral HIV load was now “consistently undetectable.”

Sheen said shame and disbelief over the diagnosis led to “an abysmal descent into profound substance abuse and fathomless drinking. It was a suicide run.”

The actor said he has now put his partying days behind him.

Sheen, the son of “West Wing” TV actor Martin Sheen, said he doesn’t feel any stigma from being HIV positive, a condition that affects more than 1.2 million people in the United States alone, according to government statistics. HIV, or human immunodeficiency virus, weakens the immune system. No cure exists, but with medical care it can be controlled. If not, one can develop AIDS.

Reaction to Sheen’s announcement was largely compassionate, and his name quickly became the top trending topic on Twitter.

“Total respect to @charliesheen opening up about his HIV positive status, may your strength be repaid and know people really do care!” tweeted Brett Herriot.