The first instalment of Stephen King's bestseller made over $700 million at the global box office, so you can be sure that there would be a second chapter. That, and the fact the Losers Club have to make good their oath to put down Pennywise once and for all.
IT: CHAPTER TWO mostly picks up a few decades after the first film, though the child cast reprises their roles in scenes set between the two eras.
Here's the final trailer of the movie, which opens Sept 5.