Braff stars as Aidan Bloom, a struggling actor, father and husband who is still trying to find his identity and purpose at age 35.
Hudson will play Braff's wife and the mother of his two children. She joins a cast that includes Mandy Patinkin and Josh Gad as Braff's father and brother, respectively, as well as Anna Kendrick, Jim Parsons and Braff's "Scrubs" co-star Donald Faison.
Braff said he "fell in love with" Hudson after seeing her Oscar-nominated portrayal of Penny Lane in Cameron Crowe's "Almost Famous," and they later became "good friends."
Braff ("Garden State") is directing from a script he co-wrote with his brother Adam Braff. Stacey Sher and Michael Shamberg are producing via their Double Feature Films banner. Production starts in August.