Country star Martina McBride used interns to do her dirty work ... so claims a former employee who says he was fired for reporting her to authorities.
Richard Hanson is suing Martina and her husband, John, claiming the McBrides hired unpaid interns and assigned them menial tasks like cleaning bathrooms, setting up and tearing down equipment, and delivering food.
The most alarming allegation -- according to docs obtained by TMZ -- is that John once sent 2 interns to his home to check for an intruder, and handed them a loaded gun for protection.
Hanson says he headed up the internship program until 2017, and continually told the McBrides the interns needed to be paid at least minimum wage. He claims his pleas fell on deaf ears. He says he filed a claim with the Department of Labor and says John fired him in retaliation.
Hanson's now suing for $1 million and other damages. We've reached out to Martina and John ... so far, no word back.