The star, who performed a show in Australia's Gold Coast yesterday (January 1), entertained the crowd for three minutes with a freestyle while the crew fixed her earpiece.
She sang: "These might not be the best lyrics I ever wrote, but whatcha gonna do? I'm in a dress that's a little bit small and little bit big and my shoes my shoes my shoes..."
Carey, who performed hit singles 'We Belong Together', 'Hero' and 'Always Be My Baby' at the show, also brought her husband Nick Cannon and twins Moroccan and Monroe on stage during the show to celebrate the New Year.
The singer appears as a judge on the new season of American Idol, which premieres on January 16.