Kelley Mack of The Walking Dead and 9‑1‑1 dies at 33 following cancer fight

Actress and producer Kelley Mack, best known for her role as Addy in Season 8 of The Walking Dead and her appearance in 9-1-1, passed away on August 2 at the age of 33 after a lengthy battle with cancer. The actress had been diagnosed with a rare form of cancer known as midline glioma, an aggressive astrocytoma that affects the central nervous system. Mack received her diagnosis in November 2024.

Family shares heartfelt tribute on Instagram

The tragic news was confirmed by her family through a touching Instagram post. “It is with indelible sadness that we are announcing the passing of our dear Kelley. Such a bright, fervent light has transitioned to the beyond, where we all eventually must go,” the post read.

“Kelley passed peacefully on Saturday evening with her loving mother, Kristen, and steadfast aunt, Karen, present. Kelley has already come to many of her loved ones in the form of various butterflies. She will be missed by so many to depths that words cannot express.”

A rising star in film and TV

Kelley Mack began her acting career in 2008 with the indie film The Elephant Garden, which won her recognition from the Tisch School of the Arts and the Student Visionary Award at the Tribeca Film Festival. She gained widespread attention for her portrayal of Adeline in seasons 8 and 9 of The Walking Dead.

Her acting credits also include appearances in Schooled, Chicago Med, and Nasty Habits. Mack also lent her voice to Spider-Man: Into the Spider-Verse and was involved in producing and starring in two projects, A Knock at the Door and Universal.

Kelley Mack is survived by her parents, Kristen and Lindsay Klebenow; her sister Kathryn; her brother Parker; and her grandparents Lois and Larry Klebenow. There has been an outpouring of love and heartfelt tributes from fans and fellow actors across social media.