Hayden Panettiere’s Ex Wladimir Klitschko Vows Their Daughter Will Always Remember Her

Hayden Panettiere's ex-fiancé and father of her daughter has spoken out following her tragic death ... sharing a heartfelt tribute that promises their child will always remember her.

Wladimir Klitschko shared the touching tribute on Instagram early Tuesday ... posting a throwback selfie with Hayden and their now 11-year-old daughter, Kaya. He wrote this is "a time of profound shock and grief" for their family and called Hayden "an important part" of his life.

He celebrated her success while also highlighting the downside of her fame, penning ... "She built an incredible career through immense talent, while also facing the darker sides of a very demanding industry. Nothing will erase the times we shared or the place she had in our lives."

Speaking directly to Kaya, he added ... "I will always speak of her mother with respect and make sure she remembers the person she was."

The Ukrainian boxer expressed his condolences to Hayden's family and asked fans to respect his family's feelings and privacy before signing off by wishing Hayden "eternal peace."

Hayden and Wladimir were together for 9 years on-and-off, splitting for good in 2018. Hayden signed over full custody of Kaya to Wladimir at the time so she could focus on treating her postpartum depression and substance abuse issues ... and Kaya moved to Ukraine to live with her father.

While on Jay Shetty's podcast this year, Hayden said she fully believed Kaya would move in with her when she felt well enough. But she explained ... "By the time I finally got healthy, I felt like it would have been unfair of me to and selfish of me to try to pull her out away from this life that she had created."

As we reported, Hayden died Sunday at the age of 36 after experiencing a possible overdose. Medics were called to the South Carolina apartment she was staying in, but she unfortunately could not be saved.