Toni Collette has signed up to Nicole Holofcener's new comedy, which also stars Julia Louis-Dreyfus and James Gandolfini.
Louis-Dreyfus will play a divorced woman whose children will soon leave home and she meets a woman (Keener) she views as the embodiment of her perfect self.
So given a new outlook on being middle-aged and single, she decides to take a chance on her new love interest (Gandolfini), but things get complicated when she discovers he's her new friend's ex-husband.
Collette will play Louis-Dreyfus' friend who also happens to be Keener's therapist, while Hewson will play Keener and Gandolfini's college-bound daughter.
Fox Searchlight will produce the as-yet-unnamed film, and they say they can't wait to work with director Holofcener.
Production president Claudia Lewis said: ''We have always admired Nicole for her unique voice and storytelling abilities. For this film she has again delivered a distinctive and relatable script that this talented group of actors can really bring to life.''