Mary J. Blige Calls Fan An 'Idiot' For Booing at Her Las Vegas Concert: Video

Mary J. Blige went scorched earth on a fan booing during her Las Vegas Residency, calling the person an "idiot" before asking for their polite removal from the theater -- and it was all caught on video!

TMZ obtained the insane footage of the iconic singer going off on the fan during her Wednesday night concert at MGM Resorts' Dolby Live Theater -- and it was totally eye-popping!

According to an eyewitness ... Mary was at the halfway mark of her 2-hour show, standing center stage at a microphone in between songs when someone in the crowd started booing.

Mary clearly heard the boos, and things quickly took a turn for the worse. The singer addressed the fan directly, saying, "To the bitch that's booing, you didn't have to come here. I hope someone sees you and politely removes you." She went on ... "The f*** are you spending your money for -- idiot!"

Ouch! Mary finally calmed down and apologized before launching back into her performance. About 20 minutes later, Mary brought out her special guest -- Wyclef Jean -- and the two belted out Wyclef's song, "911."