At the age of 30, Macklemore is a proud Grammy winner with a Platinum album and multiple hit singles, but five years ago he was still facing a dark battle with drugs. In a new special for mtvU's "Half of Us" campaign, the Seattle rapper gets candid about an addiction that almost ruined his music career.

"[When] I actually drank for the first time, I was by myself," Macklemore reveals, mapping the beginning of an addiction that quickly spiraled. "This is an indicator of who I was, from the jump. After school, by myself [at] 13 years old, maybe 14."

It's a moment that's seared into his mind, as he paints the picture vividly: At home, wearing a wifebeater, listening to Tupac and dipping into his parents' liquor cabinet. "12 shots in, [my] first time ever drinking alcohol," he said. "That's not people like, 'yo keep going.' That's me, by myself, dolo in the kitchen, like I can't stop. I can't this turn this off. This feels good, I wanna keep going."

Macklemore explained that he spent his first year of high school skipping classes to smoke weed, and struggling to write rhymes because his mind was blank. "I've been rapping since [I was] 13 or 14, and Freshman year of high school I realized that music and me did not work if I was under the influence."

His passion for music fueled an attempt to get sober, but it didn't last for very long.

"The thing that pulled me back was knowing that I wanted to be a musician, and that if I wanted to do this I had to get sober," he explained. "So I'd go a month and be sober, make a bunch of music and then fall back off and vanish for a couple months and go back and forth like that. That's how I made music for the majority of my teen years and twenties."

Next, he dabbled in Oxycontin for a brief period, describing it as one of the "most intense" drugs he's ever used. "It's synthetic heroin, that's the definition of it," and "[I saw] the grip that it had, just doing it for five or six days, sweating through my sheets and coming off of it shaking."

Though he was able to hide his addiction on a surface level, the problem became apparent to his family, and it was his father who eventually approached him about going to rehab at the age of 25. At this point, he said, his relationship with his girlfriend was also suffering immensely, describing his actions as, "The complete discarding of someone else's emotions and well-being for your own selfish needs in that moment."

"If it wasn't for that rehab center, I probably wouldn't have been here," he admits. "In terms of recovery, it has been very important for me to be a part of a recovery community, to actively be around my people because they understand me. They get it."

Hear more of Macklemore's story at "Half of Us".