Apparently, Green Day front man Billie Joe Armstrong doesn't like Justin Bieber. And he REALLY doesn't like it when his band's set is cut short. According to Billboard.com, things got ugly at the iHeart Music Festival when the band was told to cut their set short with little notice.

But just when penultimate performers Green Day were getting ready to debut new songs from "Uno!" (out Tuesday and the first of three albums due from the rock trio this fall), a teleprompter visible from the crowd suggested otherwise."One minute?!" lead singer Billie Joe Armstrong howled. "I'm not Justin Bieber, you motherf*****s! You gotta be f****n' joking. I got one minute, one minute left. Now I got nothing left. Let me show you what one minute f*****g means."

Some are confused as to why Armstrong attacked Justin Bieber, who wasn't even at the event. Word is Green Day's set was cut short to allow Usher more time on stage. And as most everyone knows, Usher was the one that helped launch "the Bieber's" career.

After his tirade, Armstrong and his bandmates proceeded to smash their guitars and stormed off the stage.

One suggestion: never invite Billie Joe to compete on "A Minute to Win It."