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.

Kelley Mack’s death shocked her loved ones. Mack’s rep told TMZ Thursday that the “Walking Dead” star’s passing at age 33 was a “total” surprise. Mack, according to her rep, was auditioning for roles earlier this summer after she underwent cancer treatment in February and experienced a “nice recovery.”