was among performers at KIIS FM's Jingle Ball concert in Los Angeles. The country-turned-pop superstar stunned the crowd who packed the Staples Center as she performed some of her biggest hits despite being ill.
"I'm about to go onstage at @1027KIISFM #KIISJingleBall in LA. Fun fact: I have a wicked case of laryngitis. This should be interesting!" she told her Twitter followers earlier on Friday, December 5.