The one thing Russell Brand wants people to know about addiction: it's an illness.

The typically goofy actor got serious in a recent sit-down with Oprah Winfrey about his past addiction to heroin and the gross misconceptions people have about the disease.

"For me, I couldn't cope with being me," says Brand, who admits he has a "very addictive personality" with many things.

"I had problems with food. Like when I first discovered chocolate as a little kid I was doing it compulsively. Then I was infatuated with pornography. And then when I discovered drugs."

Brand explains he used drugs to calm his inner turmoil and mask the pain of personal struggles. "As a little kid I was very lonely, very isolated and confused. And anything that could temporarily relieve that, I was very grateful for."

The comedian also talks about how the recent passing of Oscar-winning actor Philip Seymour Hoffman from a heroin and cocaine overdose has caused him to reflect on his own sobriety.

"When I got clean 11 years ago, I realized that the reason that I was taking drugs was to deal with those emotional issues," says the 38-year-old. "And once you stop — when you take drugs out of the equation, those issues remain. That's how someone can have 23 years clean and then use drugs again."

The death of Hoffman angered many over the lingering question, why start again after 20+ years of sobriety? Brand wants people to know that addiction is not black and white.

"The way that drug addicts regard the issue is that it never really goes away; that it's always there dormant. And if something provokes it, you'll be back out there," explains Brand.

"It's a seductive idea that maybe you can use again. Maybe you can control it. That's why I think you have to — as a drug addict, the first thing you have to do is accept you can never use…"

The actor emphasizes that people need to realize this in order to accept Hoffman's death. "[It] doesn't make sense unless you accept that addiction is an illness," says Brand. "It doesn't make sense any other way."

Watch Brand's full interview with Oprah on March 9 on OWN at 9 pm ET. Check out a sneak peek below.