'Glee' season 4 may have already begun its run between Rachel and Kurt in New York City, and the re-vamped New Directions back in Lima, Ohio, but anyone who caught the season 4 premiere "The New Rachel" may have noticed something: half the original cast was missing!  Thankfully, as the season rolls on we'll learn more of the fate of Quinn, Finn, Puck and Mercedes, but who's popping up in the latest promos for "Britney 2.0?"

They're baaack!  Finn and Puck fans rejoice, for it seems that the latest promos from 'Glee' season 4's sophomore effort "Britney 2.0" has found some of your missing cast members.  We last knew Finn to be headed out to join the Army, though he certainly doesn't look like a grunt in any of the footage we've seen thus far.  Will he walk in at just the wrong moment for Rachel and Brody in New York, or pay his respects to Lima first?

And what of Noah "Puck" Puckerman?  Will he return from his L.A. adventures to meet his previously-unknown half-brother Jake?  Are we seeing new footage from their respective returns, or simply recycled footage from last season?  And who's that familiar looking star catching Rachel and Kurt in her office?

'Glee's second tribute to Britney Spears, the appropriately-titled "Britney 2.0" debuts on Thursday, September 20 so check out the new promo and give us your theories in the comments!