Actress Hayden Panettiere's cause of death has been revealed, five weeks after she passed away aged 36. 

On September 22, it was confirmed  by the Greenville County Coroner's office to HELLO! that the American actress, best known for her roles in Heroes and Nashville, died from the toxic effects of fentanyl, 4-ANPP, Alprazolam, Methocarbamol and Quetiapine. Hayden's death was ruled an "accident."

The release stated: "First responders and Emergency Medical Services arrived on scene and located a female in cardiac arrest. EMS personnel initiated advanced cardiac life support measures; however, resuscitation efforts were unsuccessful, and the individual was pronounced deceased at 2:32 PM.  The Greenville County Coroner's Office responded to the scene and initiated a parallel investigation with the Greenville City Police Department."

A press release on August 17 from the coroner said there were "no signs of trauma." Hayden's on/off boyfriend, Brian Hickerson and his brother, Zach, found Hayden, who was reported to have suffered a cardiac arrest at the home. 

Narcan was administered by Brian and CPR was performed by the medical professionals who arrived, but Hayden was pronounced dead. 

A statement from her father Skip read: "It is with profound sadness that we share the tragic passing of our beloved Hayden.

"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."

Hayden had spent years battling drug addiction, alcoholism and depression, which she chronicled in her memoir, This Is Me: A Reckoning, released in May. 

In 2020, she spent eight months in rehab. Reflecting on her stint in her memoir, Hayden wrote: "As my nervous system tried to regulate itself without the depressant effects of alcohol, it went into overdrive, and my whole body shook, I couldn’t sleep, and my head pounded like it was pressing against my skull… A doctor told me that if I didn’t stop drinking, I'd be dead within five years."

In one of her final interviews before her death, Hayden opened up about developing postnatal depression following the birth of her daughter, Kaya, in 2014. 

"I turned to wine, which ultimately ended up leading to an alcohol dependency. It was how I would get through each day," she told the parenting outlet Momé. 

In 2018, the actress made the decision to sign over custody of her daughter to her ex, Ukrainian former boxer Wladimir Klitschko.

"I was going through a really challenging time in my life," she said. "I knew I needed to be able to put her first so that I could get the help I needed and be the mum she needed me to be."

Speaking about her relationship with her daughter, Hayden shared: "I love my daughter, and I'm so proud of the young woman she is becoming. I talk to her all the time, and I feel so connected to her. She's like a mini-me."

Hayden began her career as a child, appearing in soap operas before landing a role in the 2000 sports drama Remember The Titans alongside Denzel Washington.

She later shot to stardom playing cheerleader Claire Bennett in the superhero drama Heroes before starring as country singer Juliette Barnes in the TV series Nashville.

Her film credits include 2006's Bring It On: All Or Nothing, I Love You, Beth Cooper and appearances in the Scream franchise.

If you or someone you know is struggling with mental health challenges, emotional distress or just needs someone to talk to, support is available. In the US, you can call or text 988, or visit 988lifeline.org for free, confidential help 24/7.