Actress Kelley Mack, best known for her role as Addy in Season 9 of The Walking Dead, died Saturday in her hometown of Cincinnati. She was 33.

Her death was confirmed by her agent, Julie Smith, who said Mack had been battling diffuse midline glioma, a rare and aggressive cancer of the central nervous system.

The diagnosis, made public in January, had left her partially paralyzed, though she continued to post hopeful updates about her recovery on social media.

Born Kelley Klebenow, Mack also appeared on Chicago Med and had roles in independent films such as Mr. Manhattan, Broadcast Signal Intrusion, and Delicate Arch. 

In March, she shared a video of herself climbing stairs, a significant milestone during her treatment.

Her sister announced the news of her passing on Instagram, writing, “Kelley passed peacefully on Saturday evening with her loving mother Kristen and steadfast aunt Karen present.”

Tributes from Walking Dead co-stars poured in, remembering her as a “bright light” and “incredible human.” Director Michael E. Satrazemis called her “a bright light on every level.”

A remembrance service for Mack will be held on August 16 in Ohio.