Kelley Mack, an actress best known for her work on the horror series “The Walking Dead,” has died at age 33. A representative for Mack confirmed her death to ABC News and said in a statement, “She will be so missed.”

Kelley Mack, famous for her roles on "The Walking Dead" and "Chicago Med" has died of cancer at age 33. Her sister, Kathryn, announced Mack's passing Tuesday on Mack's Instagram page. Mack died Saturday according to the post.

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.