Mariah Carey onstage at the So So Def 20th anniversary concert on February 23, 2013 in Atlanta, Georgia. Credit: Prince Williams/Getty

It's The Emancipation of Mimi's nipple! Mariah Carey gave audience members quite a show at So So Def's 20th Anniversary Concert at Atlanta's Fox Theatre on Saturday, Feb. 23 -- but not for the reasons the American Idol judge intended.

Wearing a curve-hugging cream dress with metallic accents, the "Dreamlover" singer wheeled out a birthday cake to honor her longtime pal and collaborator, Jermaine Dupri. Unbeknownst to her, Carey's left breast briefly popped out of her dress as she waved to fans onstage.

Carey -- mom 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," she once told Allure of her sexy style. "I understand that people think I'm a ditzy moron."

Luckily for Carey, she's not the only American Idol judge to suffer a nip slip: Nicki Minaj accidentally flashed her areolas on ABC's Good Morning America in August 2011 and on BET's 106 & Park in November 2012.