Hilary Duff has paid tribute to her late friend and fellow child star Hayden Panettiere, who died at the age of 36.

Duff shared her memories in an Instagram post on Tuesday, expressing sadness over Panettiere's passing. "We lost touch through the years, but I will always remember you as so hardworking and effervescent, with that big, gorgeous smile," Duff wrote.

Duff reflected on their younger years, when they were both navigating the unique challenges of child stardom. "I remember staying up late, chatting and gossiping, and connecting because we were part of such a small sliver of people who actually understood the strange lot in life we were navigating," she stated. "We were so young, with no real idea how to make sense of any of it."

Both Duff and Panettiere rose to prominence around the same time. Duff starred in "Lizzie McGuire" beginning in 2001 and appeared in films like "Cheaper by the Dozen" and "A Cinderella Story." Panettiere gained recognition for her roles in the soaps "One Life to Live" and "Guiding Light," as well as the 2000 film "Remember the Titans."

Duff concluded her tribute by sending condolences to Panettiere's family and loved ones. "I so deeply wish this wasn't the end for you. Sending a heart full of love to your family, the many people you impacted and everyone who loved you. Rest easy."

Panettiere's death was announced by her father, Skip Panettiere, who described her as an "incredible light and a force of nature." Authorities in Greenville, South Carolina, responded to a report of an unresponsive female at an apartment and determined the cause of death to be a possible drug overdose. No signs of trauma or foul play were immediately evident in the ongoing investigation.

Other peers in the entertainment industry also shared their memories and condolences. Actress Alexa PenaVega, who also started her career as a child actor, noted the shared experiences of navigating a difficult industry. Solange Knowles, who costarred with Panettiere in "Bring It On: All or Nothing," remembered her courage in sharing her story. Paris Hilton described Panettiere as "so talented, strong, kind and full of so much love and light," while Emma Roberts offered her condolences, stating, "Rest in peace my sweet friend. You are so loved and you will be forever missed."