Charlie Sheen pens open letter about HIV diagnosis

Charlie Sheen says his partying days are over.

In an open letter on the "Today Show's" website, Sheen wrote about his experience with HIV. He said it all started when he had a three-day migraine-like headache. Sheen announced on "Today" on Tuesday morning that he received an HIV diagnosis four years ago.

"I was emergently hospitalized with what I believed to be a brain tumor or perhaps some unknown pathology. I was partially correct," he wrote. "Following a battery of endless tests, that included a hideous spinal tap, it was sadly and shockingly revealed to me that I was, in fact, positive for HIV."

He said the diagnosis was a wake-up call.

"The news was a 'mule kick' to my soul," he said.

The actor wrote that he immediately began intensive treatment under Dr. Robert Huizenga.

"Not missing a beat, a med dose, or one shred of guidance, quickly my viral loads became undetectable," he said. "Like every other challenge in my life, again, I was victorious and kicking this disease's ass." But he said at the same time, he spiraled back into drug abuse and excessive drinking.

"My medical team could only shake their heads as each and every blood test returned levels revealing a state of remission," he wrote. "Even though I might have been trying to kill myself, one thing was radically evident; the disease was not."

Sheen added that during this time of crisis, he hired prostitutes, whom he referred to as "unsavory and insipid types." He wrote that he informed them about his HIV-positive status, and in turn, was the victim of extortion and blackmail.

"To date, I have paid out countless millions to these desperate charlatans," he said. Sheen wrote that the blackmail was what finally led him to announce his status.

The former "Two and Half Men" star wrote that once treated, HIV is no different from other diseases.

He closed off his letter by saying, "My partying days are behind me. My philanthropic days are ahead of me."

His doctor, Huizenga, added to Sheen's statement and said that he believes Sheen's status as a celebrity can help raise awareness about HIV. He said, "I anticipate Charlie can save many more lives coming forward with his revelation than I could ever have aspired to as a doctor. With Charlie remaining dedicated to his treatment regimen, I expect the HIV will only minimally -- if at all -- affect his predicted life expectancy."