David Leslie Johnson, who co-wrote Conjuring 2, has been hired to pen what is being titled The Nun. James Wan, who directed the Conjuring movies, and Peter Safran, who produced them, are reuniting to produce the spinoff.

What is noteworthy about the demon nun character is that she didn’t exist until about three months before Conjuring 2 opened, as she was added during last-minute reshoots.

The studio and Wan had a cut of the movie, which stars Patrick Wilson and Vera Farmiga as paranormal investigators, in which the antagonist was a demonic figure with horns. The studio was ready to release that version, but at the last minute, Wan was struck by a revelation. And so he came up with a new concept, a demon nun, which he pitched to New Line. And even though the late-in-the-game change could have spooked some studios, New Line execs gave him their blessing.

The shoot took place in March, just three months before the movie was scheduled to open on June 10. Some of the changes were minor: The art piece that Wilson is painting was altered digitally as the horned demon made way for the demon nun. Some were more extensive, such as a set piece in which Farmiga watches in terror as a shadow crawls across the wall to line up with the painting and … (well, you'll just have to see the movie to learn more). Bonnie Aarons, under heavy makeup, played the character.

The Nun will be the second spinoff from the Conjuring series, following 2014’s Annabelle. That movie proved to be a horror hit when it ultimately grossed more than $256 million worldwide (or nearly 40 times its production budget). New Line has now slated an Annabelle sequel for 2017.

The Conjuring franchise remains popular as Conjuring 2 was not only the No. 1 film in North America but also No. 1 internationally this past weekend outside of China. It was also the biggest opening weekend ever for a horror film in 30 markets including Australia, Mexico, Brazil, all of Latin America and most markets in Asia. The movie has already grossed more than $100 million worldwide in five days of release.