Charlie Sheen appeared on the "Today" show on Tuesday morning to reveal to the world that he is HIV positive, and has known about the diagnosis for four years now. It took a lot of strength and courage for the actor to come out and admit something as serious as this for everyone to see, but he made it very clear that this is what he needed to do, and it was a relief to finally get it off his chest. His father, Martin Sheen, could not be more proud of his son for finally coming forward about this.

"He had been leading up to this sort of story for several months, and we kept encouraging him to do it," Martin, 75, said while on the podium at the eighth annual CME Group's Global Financial Leadership Conference on Tuesday, according to the Naples Daily News. "He kept backing away and backing away because it was like going to his own execution, I guess. It was the most difficult thing he'd ever done."

Martin went on to explain that he had known about his son's health issues for years and that up until Charlie physically sat down with Lauer, he still was not sure he was going to be able to go through with it. He had just seen Charlie a few nights prior, and made sure his son knew that he was behind him no matter what. He even offered to cancel the event and be there for him, but Charlie insisted he must do this alone.

"This morning, as I watched him alone, reveal his deepest, darkest secret, I couldn't believe the level of courage I was witnessing, and that it was my son," Martin continued to tell the crowd. "I left him a message, and I said that if I had that much courage, I would change the world."

Martin is no stranger to speaking out about issues as serious as this. For several decades now he has been an open activist for HIV and AIDs as well as civil, animal and labor rights causes, according to E! News. His passion for HIV and AIDS specifically, though, is one he strongly believes in fighting, as it is something that affects an estimated 35 million people worldwide, and of course, now is a very personal matter within his family.

"I just want to encourage all of you that have children, spouses, aunts, uncles, clients, that are involved in any form of addiction to realize that it's a disease and if they had cancer, you wouldn't think of them any differently," Martin explained on the podium. "But most importantly, people, and I speak from my own personal experience, most people who become addicted are looking for a transcendent experience. They are looking for one, the other, God, whatever it is, and naturally they shortcut the journey because the apparition...I hope that this day is the first day of the rest of Charlie's life as a free man."

Charlie has had a rough past and in 2011, even suffered a very public meltdown, but Martin has continued to stand by his side through it all. Even though he felt "powerless" during his son's meltdown, Martin just tried to be there for him in any way possible, as HNGN previously reported. Now that we know Martin was very aware of Charlie's health issues, it makes you realize the battle they had really been fighting as a family.

"What he was going through at that time, we were powerless to do much. Except to pray for him and lift him up," Martin told Radio Times back in May. "Only those of us that knew him understood what was going on. He was in a very desperate situation. And he was doing what he felt would get him out of it - going public. And it was very painful. No less painful for him...You can assure them you're there and you love them, but you cannot affect change. You pray for a moment of clarity, you trust in a higher power and you never, ever give up hope. Because that is a measure of despair."