Hayden Panettiere's Ex Wladimir Klitschko Posts Tribute For Her 37th Birthday

Hayden Panettiere's ex-fiancé Wladimir Klitschko is celebrating her life on what would have been her 37th birthday.

Wladimir, who is the father of Hayden's only child, Kaya, took to Instagram to memorialize Hayden alongside a throwback photo of Hayden grinning at the camera.

He penned ... "Instead of celebrating the way we had planned, today we celebrate her life, her spirit, and the love she brought into this world."

The former pro boxer went on to thank her fans, friends, and everyone who has reached out to him during this difficult time, adding ... "At a time filled with so much sadness, your kindness has reminded me that there is still so much good in humanity."

Wladimir then encouraged people to reach out to their loved ones and to always be kind, because "Love is a superpower."

He finished his tribute by speaking directly to the late actress, saying ... "Happy Birthday, Hayden. ❤️ You are loved, you are missed, and you will never be forgotten."

Wladimir originally spoke out about Hayden's death on Tuesday ... sharing a family selfie and vowing to never let their daughter forget her. He also celebrated her career, raving ... "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."

As we reported, Hayden died Sunday in South Carolina after a possible overdose. Medics were called to the apartment she was staying at with her boyfriend, Brian Hickerson, but she unfortunately could not be saved.

Hayden's mom, Lesley Vogel, seemingly blamed Brian for her death in a statement she shared earlier this week, saying her daughter's death was "due to the involvement of a toxic individual who I believe led to her death."