NEW YORK (AP) -- Green Day's Billie Joe Armstrong is headed to treatment for substance abuse. Sunday's announcement by the band's rep comes after the 40-year-old frontman had a meltdown onstage at the iHeartRadio Music Festival in Las Vegas on Friday. As Green Day was wrapping up its performance during the all-star, two-day concert, Armstrong profanely complained that the band's time was being cut short. "One minute left, one minute (expletive) left. You're gonna give me (expletive) one minute? ... I'm not (expletive) Justin Bieber, you (expletives)!" he yelled (although Bieber was not part of the night's festivities). Armstrong smashed his guitar before leaving the stage. In a statement to The Associated Press, Green Day apologized "to those they offended at the iHeartRadio Festival" and said its set was not cut short by Clear Channel, the host of the two-day festival.