Kelley Mack -- best known for her work on "The Walking Dead," has died after dealing with serious health issues.

Mack passed away Saturday evening with her mother and aunt at her side, according to her family who posted a message today on her Instagram. Mack had been battling glioma -- a tumor that forms in the brain or spinal cord.

Her family described her as a "bright, fervent light" that "will be missed by so many to depths that words cannot express."

That includes many in Hollywood, where Mack received 35 acting credits and five producing credits during her long career starting in the early 90's.

She landed her biggest role as "Addy" in season 9 of "The Walking Dead." She had parts in other TV shows like "Chicago Med" and on "9-1-1."

Mack also worked in movies and recorded a voice over for Hailee Steinfeld's character, Gwen Stacy, in the Oscar-winning film "Spider-Man: Into the Spider-Verse."

Mack was 33.

RIP.