Anna Kendrick hinted a few weeks ago on Instagram that it was coming. And if you look closely at the photo she tagged “#coveredinflour” there is an overturned cup in the midst of the flour and dough.

#coveredinflour, #totalloser (courtesy of Anna Kendrick on Instagram)

But there’s no stage and there are no members of the “Barton Bellas” to hint that “Pitch Perfect”’s viral hit was becoming legit this week.  “Cups (When I’m Gone)” now has a music video directed by “Pitch Perfect” director Jason Moore.

School kids, YouTube sirens and anyone near an empty cup, get ready for more hand-clapping and more flipping. As the Post’s Robert Samuels found, the rhythm has a  “flulike spread” in school cafeterias, especially Alice Deal Middle School’s :

“…If they didn’t have cups, the girls hammered out the rhythm with their fists. Or on empty yogurt containers. [Sixth-grade assistant principal Diedre Neal] soon realized the girls weren’t just being just rambunctious — they were all banging out the same pattern, singing the same song.

“When I’m gone, when I’m gone, you’re gonna miss me when I’m gone ...”

Even Kendrick, who’s performed the song on the late-night circuit, seemed surprised at the popularity of the one-minute a capella song in her interview earlier this week with Entertainment Tonight.

As if this wasn’t enough aca-goodness, the video comes on the heels of the “Pitch Perfect” cast’s reunion and win at the MTV Movie Awards and the Universal Pictures announcement that “Pitch Perfect 2” is in the works with original writer, Kay Cannon, for 2015. Get your cups ready.