Hayden Panettiere’s cause of death has been revealed.

The late actress, who was 36, died of the toxic effects of fentanyl, 4-ANPP, Alprazolam, methocarbamol and Quetiapine, the Greenville County Coroner’s Office confirmed to Page Six on Tuesday.

The manner of death has been ruled an accident.

911 dispatch audio obtained by Page Six revealed that she suffered a suspected overdose before being pronounced dead at the scene on Aug. 16.

Paramedics responded to a call about an “unidentified female” in “cardiac arrest” on Sunday and, within minutes, “CPR [was] in progress.”

The following day, law enforcement sources told TMZ that Panettiere’s friend called 911 at 1:51 p.m.

Emergency responders attempted to resuscitate Panettiere inside an apartment at a luxury complex with “advanced cardiac life support” and chest compressions, but she was pronounced dead at 2:32 p.m.

Police also told the outlet that the circumstances surrounding her death did not appear suspicious and there were reportedly no signs of foul play.

A source told the outlet that the actress had recently “been complaining about back pain in the past year.”

TMZ reported that just one day prior, Panettiere had hopped on a flight out of Los Angeles with her on-again, off-again boyfriend Brian Hickerson.

Hayden’s father, Skip Panettiere, confirmed the “tragic passing” to Page Six on Aug.16 “with profound sadness.”

Skip added, “She was an incredible light and a force of nature who brought immeasurable love and joy to all who knew her — and to the millions who watched her onscreen. We ask for privacy as our family takes time to process this unimaginable loss.”

Over the years, Hayden had been open about her struggles with opioid and alcohol addiction and postpartum depression.

In 2015, the “Nashville” star shared her “really painful” and “really scary” experience after welcoming her daughter, Kaya, now 11, with then-fiancé Wladimir Klitschko.

“There’s a lot of misunderstanding — there’s a lot of people out there that think it’s not real, that’s it not true, that it’s something that’s made up in their minds, that ‘Oh, it’s hormones,’” she said on “Live with Kelly and Michael.”

“They brush it off. It’s something that’s completely uncontrollable. It’s really painful and it’s really scary and women need a lot of support.”

The “Heroes” alum noted of the condition, “you think it’s ‘I feel negative feelings towards my child, I want to injure or hurt my child’ — I’ve never, ever had those feelings.”

In 2022, Hayden revealed her “secret” battle with alcoholism and opioid addiction that spiraled so far “out of control” that she “couldn’t live without” them.

The “Remember the Titans” star also admitted to turning to alcohol to cope with the hardships of parenthood.

“I never had the feeling that I wanted to harm my child, but I didn’t want to spend any time with her,” she told People, adding that she didn’t drink during her pregnancy but fell off the wagon after Kaya was born. “There was just this gray color in my life.”

Her addiction struggles caused the demise of her relationship with Klitschko, who “didn’t want to be around” her. 

When their relationship ended in 2018, she relinquished custody of Kaya to the former professional boxer and she went to live with him in Ukraine.

“It was the hardest thing I ever had to do,” she said. “But I wanted to be a good mom to her — and sometimes that means letting them go.”

Hayden most recently opened up about her battles in her memoir, “This Is Me: A Reckoning,” which was released in May, as well as during the press tour for her novel.

During a panel that month, she got candid about her “brutal” experience as a child star, which manifested into struggles during adulthood.

Just a few months later, in July, Page Six reported that Hayden canceled her appearance at Creep I.E. Con at the last minute due to an emergency.

“Hayden Panettiere has an emergency and will not be able to attend this weekend. We are looking forward to her appearing at an upcoming show,” the convention shared via Instagram at the time.

A rep for Hayden told Page Six that the cancellation was “due to a private family matter.”

If you or someone you care about is affected by any of the issues raised in this story, call SAMHSA’s National Helpline at 1-800-662-HELP (4357).