Directed by Miguel Arteta, the film is an adaptation of Judith Viorst's children's book "Alexander and the Terrible, Horrible, No Good, Very Bad Day" .
Garner is in negotiations with the movie studio to star alongside Steve Carrell, reports femalefirst.co.uk.
The film, however, will deviate slightly and centre on a boy who has a bad day and makes a magical wish that his family could suffer the same symptoms.
Garner would play Alexander's mother, while Carrell has already signed on to star as the boy's father.
Scripting has been done by Lisa Cholodenko and Rob Leiber. Shawn Levy and Dan Levine are producing it under their production company 21 Laps.