'The Conjuring' was one of the surprise hits of the summer. Usually the territory of superhero franchises and raunchy comedies, a horror movie broke the trend. One of the scariest elements of the movie was "Annabelle."

"Annabelle" is the possessed/haunted doll that was placed in the custody of paranormal investigators Ed and Lorraine Warren. While it was not directly  a part of the story in The Conjuring, the doll was the single factor that etched The Conjuring deeply into audiences' nightmares.

It made such an impact that New Line decided to make a full "Annabelle" spinoff.

The Wrap has confirmed the casting: "Annabelle Wallis ("Peaky Blinders") and Ward Horton are set to star in the low-budget horror movie 'Annabelle.'" 

The synopsis of the movie, from Screenrant:

"Assuming that Annabelle is a prequel, Wallis will likely be playing Donna, the owner and one of the victims of the Annabelle doll. According to the Warrens' account, Donna inherited Annabelle from her mother and brought the doll with her to college. Donna and her roommate Angie soon began to find that the doll would move itself around the apartment, and later the paranormal manifestations escalated as they found notes with pleas for help around their apartment and one day found that Annabelle seemed to be oozing blood.

The two students called in a medium to help them, who told them that their apartment complex had been built on the site of a field where a girl called Annabelle had been found dead. The well-meaning but naive pair decided that the best thing to do would be to invite the spirit to live inside the doll. Shortly thereafter, Donna's friend Lou (this will probably be Horton's role) found himself plagued by nightmares about the doll and one day found strange claw marks on his chest, as though something had attacked him. Soon after, the friends began to suspect that it wasn't a nice little ghost girl they'd invited into the doll at all."