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.

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 Mack’s Instagram on Tuesday.

Kelley Mack, whose TV credits included a recurring stint as Addy on The Walking Dead, has died at age 33 after a battle with cancer. Mack passed away Saturday in her native Cincinnati after suffering from glioma of the central nervous system (a type of tumor that starts in the brain or spinal cord), her …