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

The actress, who stars in the upcoming film “Amber Alert,” said that when her brother died suddenly in 2023 from cardiomegaly (enlarged heart) combined with aortic valve complications, she felt like “she lost half of her soul.”

“He was my only little brother 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 devastated,” she added. “I will never get over it. No matter how many years go by, I will never get over his loss.”

How Grief Affected Her Health

Panettiere said her body was physically responding to her brother’s death.

“I completely fell apart,” she said.

“I didn’t feel confident putting on clothes and leaving the house,” she added.

The actress said she gained 40 pounds in the days following Jansen’s death due to stress and high cortisol levels in her body.

“I had to see horrible paparazzi photos of myself coming out of Jansen’s funeral, which was in a very private place, and it was shocking,” she said. “My agoraphobia came up, which is something I’ve struggled with in the past.”

Looking back, Panettiere said she believes what she was experiencing was her body’s way of protecting itself, shielding itself from the world.

How She Found Healing Through Wellness and 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 confide in and trust.

“She gave me strength,” said Panettiere, who explained that Alton’s approach to training was not like a boot camp.

Panettiere said that in addition to Alton helping with gym workouts, they would also “go for long, nice walks where we could blow off steam, and that would be like a therapy session.”

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

“My body just started responding, not just from exercise,” Panettiere said of the positive impact the lifestyle changes had on her. “It allowed me to let go of the stress, the high expectations that I had always placed on myself.”

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

Alton shares how proud she is of Panettiere since working with her.

“She’s just been so brave,” she said. “She wanted to make a big change in her life, and to do that, you really have to be honest about where you are.”

How Panettiere is Moving Forward

Now, nearly two years after her brother’s death, Panettiere says she’s “feeling like herself again.”

The actress said she feels “content” and is focused on the things that matter most to her, including her daughter Kaya, whom she is in a relationship with her ex, Wladimir Klitschko.

“She does so many things,” Panettiere said of Kaya. “She plays golf, she plays chess. She’s been dancing since she was little and she loves to sing.”

Panettiere said she is also working on her autobiography, which will show “the real me, from my perspective.”

And while she misses Jansen, Panettiere said he will “always be by my side.”