The actress, who plays waitress Olive Snook in the US show, will take the role of a prostitute who tells a priest during a confession that she plans to kill herself on her birthday. The priest (Law & Order's Jeremy Sisto) then tries to find her to prevent her death.
Patrick Coyle, a playwright/actor-turned-filmmaker, will direct from his own script.
Chenoweth won a Tony award for her role in Broadway revival You're a Good Man, Charlie Brown. She also played Annabeth Schott in The West Wing.
Shooting begins next week in Minneapolis, claims The Hollywood Reporter.