Jessica Barrymore, who is Drew's half-sibling, was found slumped behind the wheel of her car, surrounded by dozens of white pills. The 47-year-old also had a can of energy drink propped between her legs.

According to 10News, which covers the area in San Diego where Jessica lived, the car was parked in the driveway of an apartment block, and was stopping residents from leaving for work.

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Jessica was the daughter of Drew's father John Barrymore and his third wife Nina Wayne. She had a history of drug and alcohol addiction and had been in rehab twice during her teenage years.

Drew too has suffered with substance abuse in the past, having to enter rehab at the tender age of 13 for drink and drugs.

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Jessica took to her Facebook page two days ago to post a quote from Mysteria magazine.

The quote read: 'Life doesn't always introduce you to the people you WANT to meet. Sometimes #life puts you in touch with the people you NEED to meet to Help You, to Hurt You, to Guide You, to Leave You, to Love You, and to gradually Strengthen You into the Person You Were Meant to Become.'

39-year-old Drew gave birth to her second child just three months ago, with this news undoubtably coming as a huge blow to the star.