Actress Skye McCole Bartusiak died at the young age of 21 on July 19 in her home in Texas, but the cause was unknown until now.
The child star died of an accidental overdose. The Harris County Institute of Forensic Sciences confirms to ET that it was an accident due to the combined effects of hydrocodone and difluoroethane with carisoprodol.
Hydrocodone is found in pain killers like Vicodin, difluroethane is an inhalant found in household products that can be huffed to get high and carisoprodol is a muscle relaxer.
Bartusiak's mother, Helen, told CNN that Skye was suffering from epileptic seizures a week before she died.
The star was best known for playing the role of Mel Gibson's young daughter in The Patriot. She was preparing to direct her first feature film before she passed away.
Helen told CNN, "The girl has lived such an amazing life."
ET remembers Skye in the video below.