Will Billie Joe Armstrong’s rehab keep him from appearing as a mentor for Christina Aguilera’s team on ‘The Voice’? This is one of many questions being asked by confused fans of the Green Day singer, who suffered an onstage meltdown at the iHeartRadio Music Festival in Las Vegas on Friday (September 21, 2012).

The 40-year-old appeared to become irate after claiming the band had been cut short. He yelled, “One minute left, one minute (expletive) left. You're gonna give me (expletive) one minute? ... I'm not (expletive) Justin Bieber, you (expletives)!” Quite what poor old Justin had to do with anything is unclear, though Billie Joe proceeded to smash his guitar into smithereens before being promptly carted off to rehab. In a statement apologizing for the singer’s behavior, Green Day told Facebook fans, “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 apologise to those we offended at the iHeartRadio Festival in Las Vegas. We regretfully must postpone some of our upcoming promotional appearances.” The stint in rehab marks a rough couple of weeks for the rocker, who was hospitalized with an undisclosed ailment on September 1, 2012, but recovered to perform at the MTV Video Music Awards on September 6.

According to Deadline.com, Armstrong will still appear as a mentor on ‘The Voice’ as the audition stages were taped earlier this summer. It is not clear whether Armstrong will be available for the live rounds.