Demi Moore was forced to grow up fast after watching her mother almost die from a drug overdose when she was a child.

The G.I. Jane actress relived her difficult relationship with late mum Virginia King during an interview with Harper's Bazaar, recalling one particularly painful moment in which she saved her mother's life by digging a fatal dose of pills from her throat.

"The next thing I remember is using my fingers, the small fingers of a child, to dig the pills my mother had tried to swallow out of her mouth, while my father held it open and told me what to do," Moore shared.

Moore believes the event marked the end of her childhood.

"Something very deep inside me shifted then...," she added. "My childhood was over."

Over the course of Moore's difficult upbringing, which she also details in her new book Inside Out, she moved 30 times and also endured the death of her stepfather, Danny Guynes, in 1980, after he took his own life, while she was able to reconcile with King before her death in 1998.

Moore faced her own struggle with addiction, entering treatment for drug and alcohol abuse in the mid-1980s, and in 2012, she was hospitalised after collapsing at her home in Los Angeles, and subsequently entered treatment for drug addiction and an eating disorder.

"I had absolutely no value for myself,” Moore said of her dependence on substances. "And this self-destructive path, it very quickly... brought me to a real crisis point."

In the end, Moore credits two helpful acquaintances with saving her life.

"It wasn’t clear at the time... - maybe it was divine intervention - but two people who I barely knew stepped up and took a stand for me, and they presented me with an opportunity," the Ghost star explained. "In fact, it was more like an ultimatum... unless I was dead, that I better show up. They gave me a chance to redirect the course of my life before I destroyed everything.

"Clearly, they saw more of me than I saw of myself. And I’m so grateful because without that opportunity, without their belief in me, I wouldn’t be standing here today."