Actress Kelley Mack's death came as a shock to those in her inner circle after she underwent treatment during her glioma battle. A rep for the Walking Dead alum told TMZ that her death was a "total" surprise,

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.

Kelley Mack, who played Hilltop resident Addy on 'The Walking Dead' and appeared in Dr Pepper's 'Fansville' ads, dies of a rare form of cancer at age 33.