According to NME, Green Day producer Rob Cavallo has insisted that frontman Billie Joe Armstrong's stint in rehab is "no joke".
Speaking to Rolling Stone, Cavallo - who is also the chairman of Warner Bros Records and has worked with the pop-punk veterans on classic albums such as "Dookie" and "American Idiot" as well as their latest LP, "¡Uno!" - hinted that the band's plans for the immediate future were on hold until Armstrong had finished receiving treatment.
The band have a run of tour dates scheduled to start in November, but Cavallo said: "His rehab is no joke. He's under medical supervision for a while to get him clean."
Speaking about how his treatment would impact on the band's plans, he added: "His doctors are still evaluating. All I can say is I don't know if we'll see him before or after Christmas. It's basically undetermined when he'll be back."
Armstrong checked himself into rehab for substance abuse last month after an onstage meltdown during the band's performance at iHeartRadio Music Festival in Las Vegas. Green Day bassist Mike Dirnt subsequently insisted that the band had been forced to amend plans so they could "put the life of our friend in front of everything" but was adamant that the singer would pull through despite his current issues, adding: "We're still getting ready for the next phase."??
The rest of the "¡Uno!, ¡Dos!, ¡Tre!" album trilogy will be released in two more stages, with the second LP, "¡Dos!" coming out on November 12 and "¡Tré!" on January 14, 2013. Green Day will also play a huge UK stadium show next summer. The trio will headline London's 60,000 capacity Emirates Stadium on June 1, 2013.