The bestselling author has said it has “been the most wonderful journey,” and shared a hopeful message on Twitter to anyone who may be struggling with alcohol.
“Hello! Today I’m TWENTY NINE YEARS SOBER,” she began.
"Back in January 1994 I thought my life was over. But its been the most WONDERFUL journey.
"If you’re struggling with or worried about alcohol I PROMISE you that recovery is possible, that you’ve nothing to lose but your shame.”
The Limerick native has been open about her journey to sobriety in the past, revealing to Radio 4’s Desert Island Discs in 2017: “As my addiction got worse so did my denial.
"Alcohol was the love of my life; it was my best friend.”
She also opened up about her battle with depression at the same time, saying it started “suddenly.”
“I was at a barbecue one Sunday afternoon and I started to feel intense anxiety and I couldn't understand it.
"Everything inside me started to speed up. I started to feel like I was dreaming that the people I was talking to weren't real.
"It got worse and worse... I had never experienced anything like it. I stopped being able to sleep. I stopped being able to eat. I couldn't have conversations.”
“Nothing worked but the passage of time. It ran its course. It’s an illness and it ran its course,” she said, describing her time in a psychiatric hospital made her feel “even less safe.”
Appearing on the Late Late Show last year, Marian admitted her addiction to alcohol became “the only thing I cared about eventually.”
"My drinking was never normal in that I drank for the wrong reasons. I drank because I felt being me was like wearing a pair of really tight shoes,” she said.
"Life was so uncomfortable in that prison. When I drank, it loosened and I felt like I could breathe and be normal and like how other people felt.
"Everyone was saying to me that they were worried and I just couldn't take it because I thought 'If I don't have this, I will have nothing'. I couldn't bear being me," she said.
"So I did this lacklustre suicide attempt that was probably a cry for help at the time. But it meant there was no denying how bad things were."
Marian entered rehab in Ireland, around the time she started writing.
"I started four months before I crashed and burned so spectacularly.
"I got out of rehab in March, I got a contract in June for three books. Watermelon was published 14, 15 months later."