The 'Dreamlover' singer, 42, wore a curve-hugging cream dress with metallic accents to the So So Def's 20th Anniversary Concert at Atlanta's Fox Theatre on Saturday.
As she wheeled out a birthday cake to honour her longtime pal and collaborator, Jermaine Dupri, Carey accidentally suffered a nip-slip as she waved to fans onstage, reported Us magazine.
Carey, mother to 22-month-old twins Moroccan and Monroe, with husband Nick Cannon, has never shied away from wearing provocative clothing.
"It's a dichotomy, I understand. I understand that people think I'm a ditzy moron," she once said.