Pokemon can crossover with anything. I mean think about it. If you need an edgy crossover, bam, Mewtwo can come in and shake 'em like a dog with his psychic mind powers. If you need cute: bam, Pokemon has you covered in multiple areas.
And covered Animal Crossing: Pocket shall be, as it's graced with one of the cutest creatures of them all, Eevee. According to the game's official Twitter account, starting tomorrow an Eevee crossover event will be happening. It involves "Eevee items," alongside of a quick teaser featuring the Pokemon itself and the always creepy Gyroid.
To participate you'll need to locate Poke Balls and craft items. Exact details are scarce (including the end date) but for now that's what we got.
Animal Crossing UK [Twitter]