Lily Allen has said she contemplated taking heroin while supporting fellow singer Miley Cyrus on tour.
Allen, 35, said she realised she had hit rock bottom while supporting Cyrus on her 2014 Bangerz tour.
She told DJ Fat Tony on his The Recovery podcast that she had found herself back on the road due to a lack of money following the births of her children.
She said: "I was like 14 stone and just did not feel like a pop star at all so I started taking this drug called adderall, which is like speed, to lose the weight, and I got addicted to this drug because it made me invincible and I could work really long hours and be all the people I was required to be.
"And then I ended up on tour in America supporting Miley Cyrus.
"It was when she was doing Wrecking Ball and the Bangerz tour and it was a highly sexualised tour.
"I had just spent the last three years pushing babies out. It couldn't have been less what I felt like."
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Allen said she had not been a supporting act before, adding: "I was supporting this girl who was much younger and more attractive than I felt and I just started acting out in all manner of ways.
"I started cheating on my husband and I had always really drunk alcohol to take the edge off of the drugs, and then I realised I was getting up in the morning and downing those mini bottles of vodka or whisky or whatever was left, without the drugs any more.
"I was thinking: 'I think I have got a drinking problem'. I remember being in LA and thinking: 'None of this acting out is working any more. Maybe I should try heroin'.
"But… I had been in a scene where I had seen what happens to people who use heroin, and knew that when that thought popped into my head it was time to confront my demons, and that was about five years ago. And I started recovery."
Allen said she started using online addiction recovery tool The Rooms, but added: "I got clean and at that time I wasn't really committed to the programme as a lifelong thing. I just wanted to get to six months so at least I know I can stop this when I need to.
"At six months I started drinking again and almost instantly I lost everything. I lost my marriage, I lost my house that I had worked for 10 years to buy.
"My career started sinking and I lost all my friends, I didn't have any of my friendships any more.
"I was so resentful and so angry all the time, I really felt that the world owed me stuff and I got the raw end of the deal. And that went on for another four years and then I ended up back in The Rooms again."