Hayden Panettiere 'Felt So Out of Control' When She Gave Up Custody of Her Daughter Due to Addiction Struggle: 'One of the Worst Days of My Life'

Hayden Panettiere has endured numerous hardships in her life, but the day ex-fiancé Wladimir Klitschko asked her to give him custody of their daughter, Kaya, was "one of the worst" she's experienced.

Klitschko confronted the actress about the situation when she went to visit him and their child after she finished her second stay in rehab for postpartum depression and substance abuse.

"It was a living nightmare, and I felt so out of control," she recalled of the situation in a new interview. "There’s nothing that I could do about it."

"There’s so much of me that wanted to fight, but I had to ultimately take into consideration the most important thing, which was how this was all going to affect my daughter," the Heroes alum, 36, acknowledged. "Sometimes that means having to do the hardest things in the world, for their sake."

The blonde beauty called her 50-year-old ex, who lives with Kaya in Ukraine, "an incredible father."

"I know he was doing what he felt was best for our daughter," she told Us Weekly.

Panettiere said living on separate continents makes their "arrangement even more challenging," but she will always put Kaya, now 11, first.

"It was a difficult thing to write about and still is a difficult thing for me to verbalize," the actress noted of including the story in her upcoming memoir, This Is Me: A Reckoning. "Absolutely one of the worst days of my life, and will always be."

Fortunately, the Nashville star currently has "an incredible relationship" with Kaya and the former boxer, whom she was with on and off from 2009 to 2018.

"I’m so grateful for Wlad," she raved. "We’re very close, and have had a deep friendship, along with a relationship, since I met him when I was 19."

"So to see that we still have this bond and the ability to co-parent and show our daughter [that] even though we’re not together, doesn’t mean that there’s a lack of love here, and it doesn’t mean that you’re unsafe," Panettiere explained. "And my daughter, she’s just an incredible gift. She’s otherworldly and so kind and so fierce and surrounded by good people, and it’s incredible for me to be able to watch her thrive in areas that I struggled with growing up. She’s just the best thing, all the best parts of me and Wlad."

The actress revealed that when the war in Ukraine began in 2022, she immediately flew out to be by Kaya's side.

"We watched her father and her uncle fight on the front lines," the mother-of-one recalled. "She was so brave about it, and so reasonable and rational."

"You’re afraid that if they don’t fully process their emotions, then they’re going to ignore it, and it’s going to have a terrible impact on them later in life," she spilled. "But I remember, I sat her down and had a conversation with her about the war, and I said, “Do you have any questions?” And her only question was, “Why is [Vladimir] Putin doing this?” The one question that I really couldn’t answer. I tried my best to answer it. Luckily everyone’s safe, alive and well."