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, 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.

Actor Kelley Mack, best known for playing Addy on "The Walking Dead," died over the weekend, her family announced. She was 33. "Such a bright, fervent light has transitioned to the beyond, where we all eventually must go," her sister Kathryn wrote on her Instagram page Tuesday.