Hayden Panettiere is still recovering from a devastating loss.

The Heroes alum recently opened up about losing her 28-year-old brother Jansen Panettiere suddenly in 2023 due to an undiagnosed heart condition, and the impact his death left on her.

“He was my only sibling, and it was my job to protect him,” she told People in an interview published Sept. 18. “When I lost him, I felt like I lost half of my soul.”

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

And in addition to having to grapple with an unimaginable loss, there was another factor that weighed on Hayden’s mental health following Jansen’s death: the paparazzi.

“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 explained. “My agoraphobia came out, which is something I’ve struggled with in the past.”

Adding to her reluctance to leave the house was a rapid weight gain she experienced immediately following Jansen’s passing, which she in part attributes to “stress and cortisol,” noting, “I just ballooned out.”

“I didn’t feel confident to put on clothes and get out of the house,” she explained, “but I also knew that I needed to get out and keep moving or I’d never stop looking and feeling this way. It became a destructive hamster wheel of, ‘Do I feel good enough to go out?’”

But after working with a trainer, she explained, and incorporating exercise and long walks back into her life, Hayden said she eventually felt mentally well and physically confident enough to once again walk out the door.

As she put it, “My body just started reacting, not just from the working out. It allowed me to release the stress, the high expectations I’d always put on myself.”

Coping with Jansen’s loss has also given Hayden—who shares daughter Kaya, 9, with ex-fiancé Wladimir Klitschko—a new kind of resilience.

“When something that massive has happened to you, you really learn to pick your fights and just not let the little things upset you," she explained. "Because once something so horrific, so deep, so catastrophic happens in your life, there's not much that can really rock you."

And in the year and a half since Jansen’s death, Hayden has been open about the ways she’s choosing to keep her brother close—including keeping his art, images of which Jansen often shared to social media prior to his death, nearby.

"His AMAZING paintings are what I see when I wake up and when I go to sleep," Hayden captioned an Instagram post on the first anniversary Jansen’s passing. "Rest in peace my brother. One day we'll meet again."