More proof that Britney Spears’ big Sept. 17 announcement is her Las Vegas residency

A few weeks ago we posted about a new countdown clock  on her website that was ticking down the days, minutes, hours and seconds until Britney Spears made some kind of announcement that was sure to shake the earth off its axis.

We speculated that it may be a new single, announcement of a new album, or, finally, confirmation of her long-rumored residency at Las Vegas” Planet Hollywood.

The Las Vegas stint moved to the head of the line today with this little Spears nugget from BreatheHeavy. The fan site devoted to ALL THINGS BRITNEY notes that an email was sent to employees of Planet Hollywood and its parent, Caesars Entertainment, inviting them to “the biggest announcement in Las Vegas Entertainment History” on Sept. 17.   If that bit of hyperbole doesn”t mean Britney”s coming to town, what else could it possibly mean?

The event, believe it or not, runs from 1:30- a.m. -9:30 a.m. Invitees will meet at Planet Hollywood and be shuttled to some secret underground bunker for the announcement. OK, we made up the secret underground bunker part, but apparently, the announcement will take place off site (h/t Idolator).

In the meantime, wouldn”t it be really cool if Sept. 17 were when Spears” duet with Miley Cyrus surfaced? As a reminder, producer Sean Garrett confirmed the duet with Vibe last week, calling the collaboration for  “Bangerz” “fun, exciting [music].” The only question is will they twerk together in the video?