Jessica Barrymore, who shared the same father as the Charlie's Angels star, was found slumped behind the wheel of the vehicle in National City, just north of San Diego, California. Pills were discovered on the passenger seat and a can of energy drink was wedged between her legs.
Drew Barrymore has now spoken out about the tragic news, insisting she is sad to hear about Jessica's death.
A statement from the actress reads: "Although I only met her briefly, I wish her and her loved ones as much peace as possible and I'm so incredibly sorry for their loss."
Jessica would have turned 48 on Thursday. She is the daughter of John Drew Barrymore and his third wife Nina Wayne.