The actors and production crew are staying tight lipped on how it is going to end. Lead actor James Norton, who plays evil killer Tommy Lee Royce, used just six words: "Happy Valley. The finale. That’s all."
Con O'Neill who plays Neil Ackroyd in the Sunday primetime BBC drama that has the nation gripped would only tell This Morning's Holly and Phil that the ending blew his mind, describing it as "extraordinary".
With just days to go until the finale, the excitement is building and it seems like everyone has their own theory about what writer Sally Wainwright might have planned.
