Organizers at the Geffen said on Friday that the cast also will include
"Reasons" was first performed in 2008 at the MCC Theater in New York before transferring to Broadway the following year. The play follows four characters and their debate over the importance of physical beauty.
Tamblyn will play the role of Steph, originated by Marin Ireland on Broadway. Hatosy will play Greg, her boyfriend who gets a blunt lesson in notions of what qualifies as pretty versus just "regular." The actor can be seen in the new CBS series "Reckless."
"Reasons," which is scheduled to run through Aug. 31, will be directed by Randall Arney, artistic director of the Geffen.
LaBute has seen a number of his works produced at the Geffen, including "Fat Pig" and his adaptation of August Strindberg's "Miss Julie" last season.