Hayden Panettiere has revealed how a secret addiction led to almost losing her career and her life. 

"I was on top of the world and I ruined it," The 32-year-old said as she spoke out about her dangerous addiction to opioids and alcohol for the first time. 

In an exclusive interview with People Magazine, the Nashville actress revealed her addiction started when someone on her team would give her "happy pills" before each red carpet appearance. 

"They were to make me peppy during interviews," says Panettiere. "I had no idea that this was not an appropriate thing, or what door that would open for me when it came to my addiction." 

The pills resulted in a long-running addiction that became so bad the star would "have the shakes when she woke up" that could only be cured by alcohol. 

Connie Britton and Hayden Panettiere in Nashville. (Photo / Supplied)

Panettiere, who starred as a troubled country singer Juliette Barnes in Nashville, said it wasn't long after her real-life pregnancy was written into the show when her problems began to mirror her character's. 

"Those were really tough years," said the actress, who suffered from severe postpartum depression after her daughter Kaya was born in 2015. "I could relate to a lot of those storylines like the alcoholism and postpartum depression. They hit close to home." 

The actress became increasingly dependent on alcohol to get through the day, she said. 

"I never had the feeling that I wanted to harm my child, but I didn't want to spend any time with her," she said before adding: "There was just this grey colour in my life." 

By 2018, Panettiere and her partner, former heavyweight boxer Wladimir Klitschko, who met in 2009, had split up due to the actress's need to "sneak away" and drink. 

"He didn't want to be around me," she admitted, adding after their separation, Klitschko moved back to Ukraine and the former couple decided he should take their daughter with him. 

"It was the hardest thing I ever had to do. But I wanted to be a good mum to her - and sometimes that means letting them go," she said. 

With her ex, Wladimir Klitschko, in 2013. (Photo / Getty Images) 

Soon after her daughter and former partner left the US, Panettiere's drinking worsened and she was hospitalised with jaundice. 

"Doctors told me my liver was going to give out," she recalled the scary time in her life. "I was no longer a 20-year-old who could just bounce right back." 

Finally, the actress agreed to enter rehab. 

For eight months the actress fought to "get over the hump" of her addiction but admitted to the magazine it's only recently she has" found the peace she yearned for so long." 

"I put a lot of work into myself and I had to be willing to be incredibly honest," says the actress, who underwent both trauma therapy and inpatient treatment within the last year. 

"It's an everyday choice, and I'm checking in with myself all the time. 

"But I'm just so grateful to be part of this world again, and I will never take it for granted again." 

As for what's next for Panettiere, she is set to reprise her fan-favourite character Kirby Reed in the next Scream film and is continuing to raise funds for Ukraine as the country endures its fifth month of war with Russia. 

Where to get help: 

Alcohol and Drug Helpline NZ.