UFC's Derrick Lewis Swarmed at Middle School Lunch (ADORABLE VIDEO)

UFC stud Derrick Lewis got the CELEBRITY treatment at his little brother's school ... when a faculty announced his presence and the starstruck students swarmed him like a rockstar.

Lewis -- who just beat Travis Browne this past weekend -- was having lunch with his little bro when a school faculty member grabbed the mic and told the kids a real-life UFC fighter was in the building.