Hayden Panettiere would have turned 37 this Friday, August 21. Instead, the actress has died at 36, her family and representatives confirmed Sunday night. She leaves behind her daughter, Kaya, whom she shared with former heavyweight boxing champion Wladimir Klitschko.

“It is with profound sadness that we share the tragic passing of our beloved Hayden. She was an incredible light and a force of nature who brought immeasurable love and joy to all who knew her—and to the millions who watched her onscreen,” read a statement from her father, Alan Lee “Skip” Panettiere, shared by ABC News.

Panettiere was found unresponsive at an apartment complex in Greenville, South Carolina, on Sunday afternoon and later pronounced dead, according to the Greenville Police Department. An investigation into her death remains ongoing, and no cause has been released.

“There’s an investigation ongoing,” her publicist, Kasey Kitchen, said in a statement. “We should know more tomorrow.”

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Born and raised in Palisades, New York, Panettiere began acting as an infant and was cast in “One Life to Live” at age four. She attended South Orange Town Middle School before being homeschooled through high school to accommodate her growing career. At ten, she earned a Young Artist Award nomination for her role in “If You Believe.” She went on to star as Sheryl Yoast in “Remember the Titans” and later played Kirby Reed across “Scream 4” and “Scream 6.”

During this period, she also made appearances in movies. Panettiere starred in the hit Disney sports drama Remember The Titans (2000) as Sheryl Yoast and also starred as Kirby Reed in the horror flick Scream (2011).

Panettiere became a household name playing Claire Bennet in NBC’s “Heroes,” and later took on the role of Juliette Barnes in the musical drama “Nashville,” two performances that defined her career for a generation of viewers. She also received a Grammy nomination for her vocal work on the 1998 Pixar film “A Bug’s Life.”

She had recently published a memoir, “This Is Me: A Reckoning,” reflecting on her childhood fame, motherhood, her mental health, and the loss of her younger brother. She had also spoken candidly in past years about her struggles with addiction and postpartum depression.

Panettiere’s relationship with Klitschko drew significant public attention over the years. The two met through a mutual acquaintance in 2009 and began dating while he reigned as unified heavyweight champion. They split roughly two years later, citing the difficulty of a long-distance relationship, before reuniting. Panettiere confirmed their engagement in October 2013, and the couple welcomed their daughter, Kaya, the following year. They separated for good in 2018, not long after Klitschko retired from boxing following back-to-back losses to Tyson Fury and Anthony Joshua.

That history is part of why the news has resonated so deeply across the boxing world, where tributes poured in alongside those from fans of her acting career.

Boxing community mourns Hayden Panettiere, who shared years with Wladimir Klitschko

“Damn. I hope @Klitschko is ok. This is going to be really hard on him and the family. Hang in there, Wlad. RIP,” one user wrote, reacting to ABC News’ X post.

The pain was clearly visible. Among the string of relationships she had, the one she became most best known for was the time Panettiere spent as Wladimir Klitschko’s partner. They became a couple after meeting through a mutual acquaintance in 2009.

Unfortunately, after the dating for two years, Klitschko and Panettiere decided to split, citing long-distance challenges as the reported reason.

Two years later, however, they were reunited. In October 2013, Hayden Panettiere confirmed that she was engaged to Wladimir Klitschko. A year later, she gave birth to their daughter, Kaya. In 2018, Klitschko and Panettiere finally split, this time for good. While they stayed friends, the Ukrainian, who had by then retired following losses to Tyson Fury and Anthony Joshua, received custody of their daughter.

Another fan added, “I can’t believe it. She was a sweetheart; after Wlad Klitschko KOd Chambers in 2010, Emanuel called me from Wlad’s dressing room, & I spoke to Hayden. She was so sweet, & she signed a hat for me along with Emanuel, Wlad & Vitali. May she rest in peace. 🙏🏻”

Those comments stem from Panettiere’s famous appearance at the Ukrainian legend’s 2010 title defense against Nigerian challenger Samuel Peter in Frankfurt, Germany. At the time Klitschko was being trained by the late Hall of Fame trainer Emanuel “Manny” Steward, who corned him from 2004 till his death in 2014.

Recalling Panettiere’s relationship with Klitschko, former undisputed champion Franchon Crews-Dezurn stated, “Wait, what?! Her and Klitschko were together… this is wild, so young SIP.”

“Whoa. Hayden Panettiere played iconic roles, featured in Remember the Titans, Heroes, and the Scream franchise. Was once married to boxing legend Wladimir Klitschko,” Combat Sports Editor Daniel Yanofsky wrote. “So sad. R.I.P. Save the cheerleader, save the world.”

College Hoops writer Jaden Daly stated, “Holy crap. Will always remember her as the coach’s daughter in Remember The Titans. Never knew she had a kid with Wladimir Klitschko either.”

Given the scale of her presence, which ranged across different modes of entertainment, Panettiere’s absence is clearly felt by many who still cherish her roles, especially the ones in Heroes and Remember the Titans.

Another detail that may disturb some a little is that her brother Jansen Panettiere had also died at an early age. He was 28 when he passed away from what was described as cardiomegaly, or enlarged heart, along with aortic valve complications.

Hayden Panettiere’s family has asked everyone to respect their privacy, “As our family takes time to process this unimaginable loss.”

Keeping that in mind, it should be considered a developing story with more details to emerge.