The guys have been holed up at the Sofitel Wentworth Hotel in central Sydney -- and wanted to show their appreciation to the staff ... so they got on their balconies and broke out in song AND IT'S BEAUTIFUL!!!
We're not sure which song they're singing (if you know, feel free to write in and let us know!) ... but it's an incredible sight and these dudes can SANG!!!
Good luck in the tourney ... and if the rugby thing doesn't work out, there's always "American Idol"!! (or Fiji Idol).