Green Day's Billie Joe Armstrong Seeks Treatment After Rant While the occasional onstage outburst or round of instrument destruction would seem to be well within the purview of a modern-day rock star, this behavior has led the Green Day front man Billie Joe Armstrong to seek rehabilitation after a profanity-laden rant at a performance over the weekend, the band announced on its Web site. On Friday, Green Day was performing in Las Vegas at the iHeartRadio Music Festival, a two-day event produced by Clear Channel Media and featuring top acts like Rihanna, Lil Wayne, Taylor Swift and Mary J. Blige. In mid-song a frustrated Mr. Armstrong stopped playing and condemned the show in a tirade riddled with obscene words. He pointed repeatedly to a monitor indicating that the band had only one minute left for its set - and, eventually, zero minutes - leading some observers to believe that Green Day's performance had been cut short. A brief statement posted Sunday on the band's official site read: "Billie Joe is seeking treatment for substance abuse. We would like everyone to know that our set was not cut short by Clear Channel and to apologize to those we offended at the iHeartRadio Festival in Las Vegas. We regretfully must postpone some of our upcoming promotional appearances. Green Day is on the verge of releasing three new albums, titled "¡Uno!," "¡Dos!" and "¡Tré!," between Tuesday and Jan. 15 of next year. It had also committed to a demanding promotional schedule, including many tour dates and appearances this week on "Jimmy Kimmel Live" and "The Ellen Show." It was not immediately clear which of these events had been postponed.