Lisa Marie Presley is said to have been taking opioids and weight loss medication as part of an extreme weight loss regime in the weeks leading up to her death.
The singer-songwriter was desperately trying to lose weight ahead of the award season and had wanted to "look her best" to celebrate Baz Luhrmann's Elvis biopic.
Lisa Marie had battled with opioid addiction following the birth of her twin daughters in 2008 and previously shared her story in the hope of bringing attention "on this terrible crisis".
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However, she's said to have turned back to the drugs and lost around three stone in the six weeks before the Golden Globe Awards, according to sources close to the star's family.
Insiders told TMZ that Lisa Marie had even had plastic surgery in a bid to look her best for the celebrations.
Lisa Marie attended the Golden Globes just days before her sudden death from cardiac arrest at the age of 54.
At the ceremony, she appeared unsteady as she spoke and clung to her pal Jerry Schilling while answering questions from interviewers.
In the interview, Lisa Marie chattered to Extra reporter Billy Brush and spoke of Austin Butler's performance as her late father Elvis.
Lisa Marie spoke slowly in the interview and said she needed "five days to process" Butler's performance as her father because it was "so authentic".
The star was thought to have been sober in recent years and had bravely opened up about her drug abuse in a book detailing the dangers of opioids.
"You may read this and wonder how, after losing people close to me, I also fell prey to opioids," she wrote.
Lisa Marie added: "I was recovering after the birth of my daughters, Vivienne and Finley, when a doctor prescribed me opioids for pain.
"It only took a short-term prescription of opioids in the hospital for me to feel the need to keep taking them."
She continued: "Even in recent years, I have seen too many people I loved struggle with addiction and die tragically from this epidemic.
"It is time for us to say goodbye to shame about addiction. We have to stop blaming and judging ourselves and the people around us. That starts with sharing our stories."
Lisa Marie, the only daughter of music icon Elvis, died on January 12 at the age of 54 after being rushed to hospital in cardiac arrest.
Her cause of death is still unknown as it's been deferred pending toxicology results - which could take several months.
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