*NSYNC -- Reunited ... For About a Second


It happened ... *NSYNC JUST PERFORMED ON STAGE ... but if you blinked you might have missed it.


Justin Timberlake, Lance Bass, J.C. Chasez, Chris Kirkpatrick and Joey Fatone performed together for the first time since 2003 at the VMAs ... singing a tiny bit of "Bye, Bye, Bye" during JT's giant solo number.


And then they too went bye, bye, bye.