Sam Worthington quit drinking after his wife gave him an ultimatum.
The Avatar: The Way of Water actor used to start drinking in the morning and would regularly down five glasses of champagne before a flight, but he couldn't "see" he had a problem and thought his habits were "normal".
He said: "I couldn't see it. I thought it was normal. I didn't like who I was. Drinking helped me get through the day.
"Nine out of 10 people couldn't tell. They could probably smell it on me, but when they looked at me, they couldn't tell. I was still doing my job - I just don't think I was doing it very well."
The 46-year-old actor's spouse Lara eventually pulled him "back from the brink" with an ultimatum "said with love, not anger or disappointment".
He recalled her telling him: "You can do what you want, but I don't need to be around this."
Sam - who has now been sober for eight years - admitted he was an "emotional drunk".
Asked if boozing made him "mean", he told the new issue of Variety magazine: "I was an emotional drunk.
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"I got more emotional and erratic the longer I drank. I don't think I was mean, exactly, but I could be belligerent, petulant."
The Under the Banner of Heave star suggested part of the reason why he hit the bottle was cultural.
He said: "In Australia it's ingrained in the society. We don't necessarily talk about AA and things like that. You don't recognise it's an illness, and you don't understand that some people are just wired differently."
And Sam admitted he turned to alcohol to cope with the "anxiety" of fame.
He said: "I'd go haywire over someone asking me for a photograph or taking a photograph of me. If someone approached me, my anxiety would go through the roof."