Samsung Galaxy S III running Jelly Bean ROM pops up

A Samsung Galaxy S III running an early build of an Android 4.1 Jelly Bean ROM has popped up on YouTube that seemingly looks like a leaked official build. Based on the video we can decipher that the build is pretty stable and is close to a final release build.
While the build includes all the new features added in the 4.1 update including Google’s new voice search, Google Now, expanded notifications and the new virtual keyboard, the UI remains TouchWiz Nature UX. So those who were hoping that the Galaxy S III will get dollops of the default Android Holo UI will remain disappointed, but the good news is that at least all the new features of OS release are being included.
Before this video, it was reported that Samsung might officially announce the Jelly Bean update for the Galaxy S III and the Galaxy S II at its August 29 mobile unpacked event along with unveiling a new Galaxy Note.