Hayden Panettiere would’ve turned 37 years old on Friday.

Among those mourning the actor’s death was her ex-boyfriend Wladimir Klitschko, with whom she shared a daughter.

“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 heavyweight champion posted on Facebook.

He thanked the “Heroes” star’s fans for their support.

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

Boxer Wladimir Klitschko and Hayden Panettiere attend the 34th Annual Sports Emmy Awards Reception at Frederick P. Rose Hall, Jazz at Lincoln Center on May 7, 2013 in New York City. (Photo by Jemal Countess/Getty Images)
Boxer Wladimir Klitschko and Hayden Panettiere attend the 34th Annual Sports Emmy Awards Reception at Frederick P. Rose Hall, Jazz at Lincoln Center on May 7, 2013 in New York City. (Photo by Jemal Countess/Getty Images)

Panettiere was found dead in a South Carolina home on Sunday. The Greenville County Coroner’s Office said emergency service workers responding to a woman in cardiac arrest pronounced the Rockland County, N.Y. native dead at 2:32 p.m. A toxicology report is being conducted to determine her cause of death.

TMZ said a “bag of medication” and Narcan were found in the property where she’s believed to have died.

Several of her close pals, including stylist and photographer Emily Buckingham, shared birthday messages with US Weekly.

“We experienced so many eras together, and no matter what life brought us, we always stayed connected and supported one another,” she said.

Panettiere’s body was discovered in a living room chair while her boyfriend slept in the bedroom of a Greeneville apartment, TMZ reported.

Friends and family said after her death that the actor’s relationship with on-again, off-again boyfriends Brian Hickerson was a cause for concern. He was charged with abusing her in the past, but hasn’t been accused of wrongdoing relating to her death. His lawyer called for patience in a statement obtained by the Daily News on Friday.

“Hayden’s death remains under investigation and it is important to allow that investigation to proceed,” attorney Sloan Ellis said. “As has been publicly reported, police confirmed there were no signs of foul play. Out of respect for Hayden’s loved ones and the ongoing investigation, there will be no further comment at this time.”