Serving in the military isn't all business.

Like the famed guards standing outside Buckingham Palace, ceremonial guardsmen in the United States Air Force cannot smile. To test their resolve, the Air Force's Honor Guard Tech School puts prospective guardsmen to the test:

To be a Ceremonial Guardsman in the United States Air Force you have to maintain bearing at all times, even if you have a rubber chicken in front of your face. The instructors at the USAF Honor Guard Tech School constantly challenge the newcoming Airmen's bearing, and the students pay the penalty if they cannot maintain it.

This clip first surfaced in 2012, but is only now going viral. It's enough to put a smile on anyone's face.

More From TheFW