Actress Kelley Mack, best known for her role as Addy in Season 9 of The Walking Dead, has died at the age of 33 following a battle with diffuse midline glioma — a rare and aggressive form of cancer affecting the central nervous system.
Her family confirmed that she passed away on August 2, surrounded by her mother and aunt.
In a heartfelt statement, they described her as “a bright, fervent light” who “will be missed to depths that words cannot express.”
Born Kelley Klebenow, she grew up in Ohio, North Carolina, and Illinois before graduating from Chapman University in 2014.
She had spent the last decade living and working in Los Angeles as an actress, writer, producer, and voiceover artist. She was the oldest of three siblings, including actor Parker Mack.
Mack had shared her diagnosis in January, revealing that she began experiencing severe back and leg pain before doctors discovered the glioma.
A biopsy surgery caused her to lose mobility in one leg and most of the other, forcing her to rely on a wheelchair and walker.
Diffuse midline gliomas are extremely rare tumors found in the brain or spinal cord.
The National Cancer Institute estimates fewer than 4,000 people in the U.S. are living with the condition. Symptoms may include difficulty with balance, double vision, or limb weakness.
The five-year survival rate is just over 42%, and treatment options include surgery, chemotherapy, and radiation.
Mack’s other screen credits include Penelope Jacobs in Season 8 of Chicago Med and Alice in the indie horror film Broadcast Signal Intrusion.
Her family announced that a memorial service will be held on August 16 in Glendale, Ohio, with a separate celebration of life planned for Los Angeles.