Kelley Mack, who portrayed Addy in Season 9 of The Walking Dead, has died at the age of 33. Her family announced that Mack passed away on Aug. 2 in her hometown of Cincinnati following a diagnosis of glioma of the central nervous system.

Kelley Mack’s death on Aug. 2 at age 33 was "very unexpected," her rep tells PEOPLE. The 'Walking Dead' actress was still auditioning in June despite her cancer diagnosis and her agents were "totally surprised" by the news.

Kelley Mack, an actor who starred in "The Walking Dead," died due to complications from the COVID-19 vaccine. Actor Kelley Mack, who was best known for playing Addy on the TV show "The Walking Dead," died at age 33 on Aug. 2, 2025, her sister announced in an Instagram post .