Gladys Knight might've just proved blood isn't always thicker than water -- she just sued her son to stop using mama's name and face in the restaurant biz.
Gladys wants the person now running the restaurants previously managed by her son, Shanga Hankerson, to 86 her from signs and promotions for the chicken and waffle joints.
Gladys says she gave the green light to use her name and image for the restaurants back in '99, but put the kibosh on the deal a few months ago after the eateries were raided by the Georgia Department of Revenue. Her son was arrested for allegedly pocketing a million bucks.
And one more thing ... in addition to money and an injunction, Gladys wants all her memorabilia adorning the restaurants returned to her.