Drug and alcohol use have marred Sheen's personal and professional life in recent years

New York

: Former "Two and a Half Men" star Charlie Sheen says he has the HIV virus.

In an interview Tuesday on NBC's "Today," the 50-year-old Sheen says he tested positive for the virus that causes AIDS.

"It started with what I thought was a series of crushing headaches," the 50-year-old actor said in his interview to Matt Lauer. Sheen revealed in that he was diagnosed over four years ago but had no clue how he contracted it. "I thought I had a brain tumor. I thought it was over", he said. He confessed for the first time how he had talked about his illness only to a few people he thought he trusted, but some of them 'extorted' millions out of him to keep it a secret. With his interview to "Today", Charlie Sheen said he aimed to put an end to the endless speculations about his health and to the blackmail he was facing. "I think I release myself from this prison today," he said. Drug and alcohol use have marred Sheen's personal and professional life in recent years. He was kicked off CBS' "Two and a Half Men" in 2011 after an explosive meltdown that included calling the show's producer "a contaminated little maggot."

His escapades have also included the revelation that he spent more than $50,000 as a client of "Hollywood Madam" Heidi Fleiss' prostitution ring.

"Two and a Half Men" debuted in 2003 and starred Sheen as womanizing bachelor Charlie Harper. It made Sheen one of TV's highest-paid actors and at its peak was TV's most-watched sitcom.