It's wasn't Selena Gomez's performance that stole the show at this year's annual star-studded KIIS-FM Jingle Ball concert in Los Angeles on Friday night. Instead, she captured headlines for dropping an F-bomb during an on-stage tantrum.

Us Weekly reports that the 21-year-old singer shouted a curse word out of frustration as she was experiencing audio and microphone malfunctions.

"What the f--k?" she yelled at crew members.

"She for sure said 'what the [expletive],' ... You could hear it crystal clear," a concertgoer told E! News.

Shortly thereafter, she returned to the stage to give an apology.

"Sorry, the sound isn't working!" Gomez told the crowd.

"Are you guys having a good night? I promise, a lot cooler people are gonna come out tonight," she added, according to Celebuzz. She then promised to perform two more hits, but instead dropped the mic and walked off the stage after singing one song. 

Later that night, singer Ariana Grande also had technical difficulties when she hit the stage, however, she decided to use a more professional demeanor to handle the situation.

She profusely apologized to the crowd, reports the LA Times, saying, "I'm sorry the mix was off the entire time. At least you know I'm not tracked," which could have been taken as an indirect jab at Gomez.

Other performers at Jingle Ball included Miley Cyrus who gave a naughty performance, twerking on Santa Claus, Robin Thicke and Macklemore & Ryan Lewis who were just nominated for seven Grammys earlier that night.