Jon Gruden is back to work ... but it ain't in the NFL -- or America, for that matter -- it's with a European football team as an advisor.
The Milano Seamen of the European League of Football announced the hire on Wednesday ... saying the former Super Bowl-winning coach has joined the staff to "help us to improve our organization in every aspect."
The team also shared a pic of 60-year-old Gruden decked out in Seamen gear ... and revealed he's already started to work with current staffers.