The Walking Dead actress will portray a character named Allison Stone in the found-footage film about a group of high school students recording the the aftermath of a devastating tornado, reports Deadline.
Callies is said to be shooting both The Walking Dead and the movie, which was previously called Category 6.
The project is directed by Steve Quale of Final Destination 5 and written by John Swetnam.
Callies will join the previously-announced Alycia Debnam Carey and Arlen Escarpeta.
The Walking Dead ended its second season back in March and will return for a third season.
Watch a trailer for The Walking Dead's season two below: