Lily Allen celebrates 18 months 'clean and sober'

Lily Allen has reached a sobriety milestone of 18 months.

The singer celebrated her achievement in a post to Instagram, declaring she had been "clean and sober" for a year and a half.

"18 months clean and sober today. Would recommend!" the 35-year-old wrote.

Read more: Lily Allen vows to cut down on phone time

Allen posted several snaps of herself, including one of her holding up a keyring which read: "Clean and serene for eighteen months."

The Smile hitmaker has been candid about her substance abuse in the past and recently divulged that she turned to drugs while on tour with Miley Cyrus in 2014 in a bid to lose weight.

Allen has reflected on that period of her life in her 2018 memoir My Thoughts Exactly, saying she had slept with female sex workers on the tour while she was away from then-husband Sam Cooper.

She explained on podcast The Recovery that she was at such a low point in her life that she also considered using heroin.

Watch: Lily Allen on how she came to realise she needed to get sober

“I’d been in a scene, you know, where I had seen what happens to people who use heroin and knew when that thought popped into my head it was time to – you know – confront my demons,” Allen said.

“And that was about five years ago. And I started recovery.”

Read more: Lily Allen and David Harbour share wedding snaps

However, the star relapsed after six months and began drinking again, only for her life to fall to pieces.

"I lost my marriage, I lost my house that, you know, I’d worked for 10 years to buy,” she said.

“My career started just sinking. And I lost all my friends. I didn’t have any of my friendships any more.”

While at the time of the podcast recording Allen said she didn't have a sponsor, she said she writes a gratitude list every morning to keep her "in check".

She shares two daughters with Cooper: Ethel, nine, and Marnie, seven.

Allen married American actor David Harbour in a low-key Las Vegas ceremony last year.