Gladys Knight's Chicken & Waffles Joints Raided

1:45 PM PT -- A rep for Gladys tells TMZ the singer "lent her name to her son's restaurants in the Atlanta area, similar to a celebrity endorsement. Ms. Knight was not involved in any way with the operation of the restaurants and she is sure that her son and his business partners will rectify the situation."

Gladys Knight's Chicken and Waffle restaurants just got shut down by Georgia authorities.

We're told agents with the Georgia Dept of Revenue raided all 3 of Knight's chicken joints Tuesday morning ... clearing out customers and ordering employees to leave.

Agents removed computers, files, and the contents from safes.

Gladys' son -- who runs the business -- is reportedly at the center of the investigation. It appears authorities believe $1 million may have been inappropriately diverted.

We reached out to Gladys ... so far no word back.

Story developing ...