Starring Dominic West, Maura Tierney and Sanaa Lathan, the series explores the emotional and psychological effects of an affair that destroyed two marriages, and the crime that brings these individuals back together.
Anna Paquin (True Blood) joins the final season as a series regular. New guest stars in Season 5 include Jennifer Jason Leigh, Claes Bang and Lyric Bent, with Russell Hornsby returning.
Season 5 will chronicle the aftermath of last season's horrific events and find the characters coming to terms with the consequences of their choices - as they make the realisation that if they really want to change their futures, they must first face the past.
Helen (Tierney) begins the season involved in an intoxicating new affair with a charismatic movie star (guest star Claes Bang), who offers to give her everything she's been missing.
Noah (West) meanwhile has to swallow his pride and his jealousy and step in to take care of his family in her absence.
But just when things seem to have stabilised, a chance encounter with someone from the distant past sets in a motion a sequence of events that brings them both to their knees.
Paquin stars as Alison and Cole's now adult daughter Joanie Lockhart, who returns some years in the future to piece together the truth about what happened to her mother, bringing the whole story full circle.
In addition to West, Tierney and Paquin, Season 5 series regulars include Julia Goldani Telles and Jadon Sand as Noah and Helen's children, Whitney and Trevor Solloway; and Lathan, as Janelle, Noah's girlfriend and the principal at the school where he teaches.
The series was created by playwright, writer, executive producer and showrunner Sarah Treem (House of Cards, In Treatment).
The Affair is also executive produced by Jessica Rhoades (Sharp Objects), Hagai Levi (In Treatment) and Michele Giordono (Nurse Jackie).