Hayden Panettiere on how she found healing after her brother's death

Hayden Panettiere is opening up about her late brother, Jansen Panettiere, almost two years after his death.

The actress, who is starring in the upcoming film "Amber Alert," said that when her brother died suddenly in 2023 from cardiomegaly (enlarged heart) coupled with aortic valve complications, it felt like she "lost half of my soul."

"He was my only sibling, and it was my job to protect him," she told People in an interview as the magazine's new cover star.

"I will always be heartbroken about it," she added. "I will never be able to get over it. No matter how many years go by, I will never get over his loss."

How grief affected her health

Panettiere said that body physically reacted to her brother's death.

"I just ballooned out," she said.

"I didn't feel confident to put on clothes and get out of the house," she added.

The actress said that in the days after Jansen's death, she gained 40 lbs due to stress and high cortisol levels in her body.

"I had to see horrific paparazzi pictures of myself coming out of Jansen's funeral, which happened in a very private place, and it was shocking," she said. "My agoraphobia came out, which is something I struggled with in the past."

Looking back on it, Panettiere said that she thinks what she was experiencing was her body "protecting itself, shielding itself from the world."

How she found healing through wellness, exercise

Last year, Panettiere's publicist introduced her to personal trainer and CEO of M/BODY, a barre experience, Marnie Alton, who not only helped the actress get fit, but also became someone she could vent to and trust.

"She empowered me," said Panettiere, who explained that Alton's approach to exercise wasn't like boot camp.

Panettiere said that along with Alton's help in getting her to work out in the gym, the duo would go on "long, beautiful walks where we could vent, and it would be this therapy session."

Their friendship blossomed and Panettiere said that Alton became her life coach.

"My body just started reacting, not just from working out," Panettiere said about the positive impact the lifestyle changes had on her. "It allowed me to release the stress, the high expectations I'd always put on myself."

"There's nothing like looking in the mirror and feeling like you look good enough to walk out the door," she added.

Since working with Panettiere, Alton talked about how proud she is of the actress.

"She has just been so courageous," she said. "She was wanting to make a big change in her life, and in order to do that, you have to be really honest about where you're at in the now."

How Panettiere is moving forward

Now almost two years after her brother's death, Panettiere said that she's "starting to feel like myself again."

The actress said that she feels "content" and is focusing on things that matter to her most, including her daughter, Kaya, who she shares with her ex, Wladimir Klitschko.

"She does so many things," Panettiere said about Kaya. "She golfs, she plays chess. She's been dancing since she was little and loves singing."

Panettiere said she is also working on her autobiography, which will showcase "the real me, from my perspective."

And while she misses Jansen, Panettiere said he "will always be beside me."