The death of US actress Hayden Panettiere has been ruled accidental.

The Greenville County Coroner’s Office previously determined she died from the combined toxic effects of several substances, including fentanyl and alprazolam, an anti-anxiety medication.

Now the Greenville Police Department has confirmed the death was “accidental”, saying the ruling brought its investigation into her death to a close.

Know the news with the 7NEWS app: Download today

Panettiere died on August 16 at the age of 36 after she was found unresponsive in a residence in Greenville, South Carolina.

Emergency crews attempted to revive the Heroes and Nashville star after she was found in cardiac arrest, but she was pronounced dead at the scene.

“It is with profound sadness that we share the tragic passing of our beloved Hayden,” representatives for the star confirmed to ABC News in the US at the time.

“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.”

From child star to Hollywood fame

Panettiere started acting in commercials before transitioning to soap operas and child stardom in films such as Remember The Titans.

She achieved global fame as the indestructible cheerleader Claire Bennet in the NBC series Heroes and later earned Golden Globe nominations for starring as country star Juliette Barnes in Nashville.

Be the first to know:

Panettiere has been candid about her struggles from child stardom through adulthood and recently released a memoir titled This Is Me: A Reckoning.

The raw account explored fame, motherhood, addiction, grief and family relationships.

Panettiere recently released a memoir titled This Is Me: A Reckoning. Credit: Goodreads

Emotional tribute from former partner

Panettiere and former heavyweight boxing champion Wladimir Klitschko had a high-profile, on-and-off relationship spanning nine years, which included an engagement and a daughter, before they split up permanently in 2018.

When the pair split, Klitschko and their daughter Kaya moved to his home country, Ukraine.

In 2018, Klitschko received full custody of their daughter amid the star’s battle with addiction to alcohol and pills.

Shortly after her death, Klitschko shared an emotional tribute to the actress on what would have been her 37th birthday.

“Today is Hayden’s birthday. Instead of celebrating the way we had planned, today we celebrate her life, her spirit, and the love she brought into this world,” he wrote on X.

“I want to thank all of Hayden’s fans, friends, and everyone who has reached out for the incredible outpouring of love and support.

“At a time filled with so much sadness, your kindness has reminded me that there is still so much good in humanity.”

Klitschko encouraged Panettiere’s fans to honour her memory by showing compassion to others.

“If you’re reading this, I ask just one thing: even if only for a moment, think about LOVE. Reach out to a friend. Forgive someone. Be kind,” he wrote.

“Love is a superpower. Use it.

“Happy Birthday, Hayden. You are loved, you are missed, and you will never be forgotten.”