Deryck Whibley was warned by doctors he was just one drink away from death.
The Sum 41 frontman was hospitalised with liver and kidney failure due to excessive drinking in May 2014, and issued a stark warning by medics that he had to give up alcohol for good.
He said: "At that point when I was in the hospital, they were saying one more drink would kill me at that point or give me cirrhosis or something. They didn't even know how bad it was going to be.
"It took a while before I was able to find out there was no permanent liver damage. But that first period there was definitely no way I could have another drink. It was like, 'You're done.' "
Deryck is still adjusting to life without alcohol and though he currently has no urge to drink, he knows he may not feel like that again.
He said: "It's just sort of learning how to be me without it. I didn't really know who that person was because I'd never met that person yet. From like 17 years old 'til 34, there weren't too many days sober.
"I don't plan on drinking again and I don't have any urges or thoughts and that's great but I also know that may never last. It might not last forever. It could be 20 years from now. I have no idea."
The 36-year-old rocker - who is married to Ariana Cooper and was previously wed to Avril Lavigne - has penned a new Sum 41 album, '13 Voices', and the record takes its title from the "chaos and noise" in his head that left him fearing he was "going crazy".
He said: "It was just sort of a very uncertain time. A lot of insecurities. I actually thought I was going crazy at one point. I thought I was turning schizophrenic or something.
"I had so much chaos and so much noise in my head.
"Everything was a question, which is where the term '13 Voices' came from."
The 'Fatlip' hitmaker gets more enjoyment out of performing live how he is sober.
He explained: "I feel it more. You notice it more. And what I also notice more is the audience reaction. You see it.
"But when you're drunk you don't really think about it. When you're sober you can see the emotion, someone singing back lyrics, not because they know them but because it meant something to them at a certain point in your life."