The Oscar-winning actor, 82, battled alcoholism during his early career, going teetotal following a talk with a woman from Alcoholics Anonymous in December 1975.
To mark the anniversary, Sir Anthony posted a video to Twitter, saying 2020 had been a year “full of grief and sadness” but urging those struggling not to give up.
He said: “45 years ago today, I had a wake-up call. I was heading for a disaster, I was drinking myself to death. I’m not preachy but I got a message, a little thought that said, ‘Do you want to live or die?’ And I said, ‘I want to live’ and suddenly the relief came. And my life has been amazing.
“I have my off days and sometimes little bits of doubt and all that but all in all I say, hang in there.
“Today is the tomorrow you were so worried about yesterday. You young people, don’t give up, just keep in there, just keep fighting. Be bold and mighty forces will come to your aid. That sustained me through my life.”
With gratitude, I celebrate 45 years of sobriety. pic.twitter.com/fxzMRGlI4m
— Anthony Hopkins (@AnthonyHopkins) December 29, 2020
He added: “Happy New Year this is going to be the best year.”
Welsh-born Sir Anthony, one of the most gifted actors of his generation, is perhaps best-known for playing cannibalistic serial killer Hannibal Lecter in 1991’s The Silence Of The Lambs, for which he won the Academy Award for best actor.
He discussed his alcoholism during a speech with students near his home in California in 2018, reflecting how drinking marred his early career.
He said: “Because that’s what you do in theatre, you drink. But I was very difficult to work with, as well, because I was usually hungover.”
Sir Anthony added he had been “disgusted, busted and not to be trusted” while he was drinking.
He said a woman from Alcoholics Anonymous asked him, “why don’t you just trust in God?” and from then on the urge to drink was “never to return”.