If you still haven't seen Split after its immense box office success, there will be SPOILERS below, so read on at your own risk. Fans were treated to quite a surprise at the very end of Split, which confirmed that this movie, which was shot in and set in director M. Night Shyamalan's hometown of Philadelphia, Pennsylvania, was actually connected to one of the filmmaker's previous movies. Over the weekend, the filmmaker revealed that he already has a treatment for this film already done. This is your last chance to avoid SPOILERS so read on at your own risk.

Like most of M. Night Shyamalan's movies, Split is set in the director's hometown of Philadelphia, Pennsylvania. And fans got quite the surprise at the end of the thriller, when it was revealed that this story is set in the same universe as Shyamalan's 2000 hit film Unbreakable. The scene in question happens just before end credits, set in a Philadelphia diner where there is a news report playing about James McAvoy's Kevin, who's earned the nicknamed "The Horde," since he plays host to 24 different personalities. A woman in the diner recalls another strange criminal with a name she can't quite place. We then see Bruce Willis reprising his Unbreakable role as David Dunn, telling the woman she's thinking of Mr. Glass (Samuel L. Jackson). The director took to Twitter this weekend, and while he didn't specifically mention his Unbreakable sequel, he did say that he has an 11-page treatment for his next film. Here's what he had to say on Twitter.

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"O have an 11 page outline for my next film in my bag. I can't tell you what it is, but If you've seen #Split..."

Before the surprising final scene, there was never any other indication that Split was tied into the Unbreakable story, but there has been talk of an Unbreakable sequel in the past. Back in March 2015, pop culture icon Patton Oswalt pitched an elaborate idea for an Unbreakable trilogy to M. Night Shyamalan on Twitter, and just a few months later, the director said he was "thinking about something," in regards to an Unbreakable follow-up. The director also revealed on a recent podcast appearance that there were originally more Easter Eggs that reference the Unbreakable characters. Here's what he had to say below.

"In the script, there were more Unbreakable Easter Eggs, and I had to pull them out. There were things alluding to what's happening in the city, and with the kind of the mania that is happening in the city. And it kept referencing... there was a version of the script, and I was shooting it, where they were actively battling. Mr. Glass and David Dunn. They were actively continuing to battle. And that was so distracting from the movie. Literally, the only CGI shot from the movie was like helicopters in the background, with a burning building, where they are talking in the background and [the press] reference it, and they go, 'See?' And you are wondering, 'What's going on? What's going on?' And then you get to the end. We shot that. [But] that it was going on in real time confused people. At least, in my office. 'Wait a minute? When is this? Is it the same time period, or if this 15 years later?'"

It's possible those discarded ideas may be used for Unbreakable 2, which the director confirmed earlier this week that he is going to start writing soon. Still, the filmmaker said he wasn't guaranteeing anything because he didn't know "what the demons" would do when he actually sat down to write, referring to the "demons" he confronts when he writes his screenplays. Unbreakable hit theaters in 2000, earning a solid $95 million domestically and $248.1 million worldwide, from a $75 million budget. While it's definitely not M. Night Shyamalan's biggest hit as a director, it is the one movie fans keep asking for a sequel to, and now that may finally happen, thanks to the success of Split. Take a look at M. Night Shyamalan's tweet about Unbreakable 2.