Hilary Duff is remembering her old friend Hayden Panettiere after the actress' tragic death.

On Tuesday (August 18), the "Mature" singer penned a tribute to Panettiere on Instagram following her death at 36, reflecting on the bond they shared for both growing up as child actors. While they may have drifted apart over the years, Duff still looks back at their friendship with fondness.

"Sweet Hayden. Really tough hearing this news. We lost touch through the years but I will always remember you as so hardworking and effervescent, with that big, gorgeous smile," she said. "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.. so young, with no real idea how to make sense of any of it."

Duff continued, "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 died August 16 at 36 years old after she was found unresponsive at a residence in Greenville, South Carolina. According to People, officials were heard discussing discussing an "overdose" and "cardiac arrest" around the time workers responded to the scene. The Greenville County Coroner's Office later said that responders arrived to find a female in cardiac arrest, later identified as Panettiere, and despite resuscitation efforts, she was pronounced dead at the scene.

Following news of her death, tributes from friends and colleagues poured out on social media mourning the heartbreaking loss, including her ex-fiancé Wladimir Klitschko.

OMG! That other chick is like wtf is happening right now

You know, just shaping up that face