When is a movie not a movie? When it’s actually a secret sequel (a legacyquel, really) to another movie.

You may have seen a teaser last spring for something called The Woods. There wasn’t a lot of info about the movie given at that time; just that it was the latest horror flick from You’re Next and The Guest director Adam Wingard and writer Simon Barrett. But now, just before The Woods was about to have its big public debut at Comic-Con 2016, there’s a swerve: The Woods was just the working title, created to disguise the film’s true identity as a sequel to the 1999 found footage horror classic, The Blair Witch Project. This new movie is really called Blair Witch.

Entertainment Weekly has the full details, as well as a new trailer for the movie under its proper title. Of the deception, which was described by one Lionsgate executive as something engineered with “CIA-level security,” Wingard said:

The Woods was our working title. When we signed on to it, we knew that [the name] was eventually going to be changed. To us, it wasn’t even going to be part of the marketing. But I think Lionsgate made a really smart decision, using that.

Lionsgate owns Artisan, the company that released the original Blair Witch, and they’ve experimented with possible ways to return the franchise to movie theaters for several years. After seeing V/H/S and You’re Next, they knew Wingard and Barrett were the men for the job. The secrecy around the shoot was so tight even members of the production didn’t know what they were really making. Wingard told EW that a production manager complained that the movie was cool but “[seemed] like a real knock-off of The Blair Witch.” Whoops.

We’ve seen little surprise horror movies pop up out of nowhere in recent years; 10 Cloverfield Lane being the most recent example. But introducing a movie under one title only to reveal the real name later is a pretty unique switcheroo, and while a Blair Witch sequel has failed in the past (unless you listen to ScreenCrush editor Britt Hayes, who feels differently about Book of Shadows), Wingard and Barrett are legitimate talents, and their Blair Witch has a really intriguing premise involving the brother of one of the original victims returning to the notorious woods to try to find out what happened to his sister. I’m excited to see it; Blair Witch opens in theaters on September 16. If that goes well, Wingard and Barrett even have an idea for a sequel. Hopefully they give us a little more advance warning for that one.