According to this report, Animal Crossing: New Horizons will be putting in an appearance at Jump Festa '20, which will be taking place at Makuhari Messe on December 21st and 22nd.
Photo-opportunities with Tom Nook, Timmy & Tommy, K.K. Slider, and Isabelle will be available, much like they were at Nintendo Live 2019 this past weekend.
There's no confirmation that the game will be playable there, yet, though. However, at that point it will only be a few months away from release, so hopefully we'll get some sort of information, whether a demo is available at the event or not.
Honestly, I wasn't even sure whether to post about the news until I looked up the date for the event - when they said '20, I thought that they meant that it would be taking place in January or February. But nope!
It sounds pretty similar to the game's promotional presence at Nintendo Live 2019, except with less characters available (only Tom Nook and Timmy & Tommy - no K.K. or Isabelle; I guess that plans changed for the latter two ).
Oddly, there's seemingly nothing suggesting that the game, which is now only a few months from release, will have a playable demo build at the event - only that other games will be playable. I'm starting to wonder if it's going to be delayed again, as a result. Hopefully we'll get an Animal Crossing Direct soon that will assuage that concern.