The singer checked into a treatment facility for substance abuse last month following an onstage breakdown at the iHeart Radio Music Festival in Las Vegas.
The American Idiot hit-makers pulled out of appearing at this weekend's Voodoo Music + Arts Experience festival in New Orleans, Louisiana, and now they have announced they are scrapping all of their upcoming shows so Armstrong can focus on his recovery.
A post on the band's website reads, "Green Day announced today they will cancel their club tour that was due to launch in Seattle at the Paramount Theatre on September 26th and wind down... on December 10th. Tickets for these clubs shows will be refunded at point of purchase.
"Additionally, Green Day will postpone all scheduled appearances for the months of January and February 2013. New dates for these rescheduled shows will be announced shortly and previously purchased tickets will be honored on the new dates."
Bassist Mike Dirnt says, "Obviously the timing for this isn't ideal, but Billie Joe's wellbeing is our main concern. We are happy to say that Billie Joe is doing well, and we want to thank you all for the outpouring of support and well wishes that we have received, and we can't wait to see you all again soon."
Nonetheless, to appease fans, the band is now bringing forward the release date of its upcoming album ¡Tre!.
Drummer Tre Cool adds, "We feel bad we have to delay our tour, so to make up for it we want to give our fans the music earlier than we had planned. If we couldn't be there to play it for you live, the least we could do was give you the next best thing."
The album will now hit shelves on December 11th, instead of January 15th.