Matthew Jocelyn will direct the play that centers on a woman who walks away from her entire life, including her home, family and career. Performances run March 1-22 in Toronto.
Parker, who is also known for her screen work in "Deadwood," will star in the title role. Stephens is currently represented on Broadway and in London with his acclaimed play The Curious Incident of the Dog in the Night-time. His plays also include Punk Rock and Port.
The play received strong critical notices when it premiered Off-Broadway at the Atlantic Theatre Company in 2010.
Harper Regan, according to Canadian Stage, "follows a woman's struggle to balance the difficulties of her personal and family life. One autumn evening, after learning of her father's illness, Harper Regan (Parker) walks away from her job, her home, her husband, her daughter, and doesn't look back. Harper tells no one where she's going or whether she's coming back, putting everything she's ever worked for at risk. Her journey explores the relationship between death and sexuality, the meaning of loyalty and the bonds of family."
Additional casting will be announced shortly. For tickets and further information visit Canadianstage.com.