When Green Day announced that they were releasing three albums of new material in five months it sounded like serious heavy lifting for the veteran punk band.

And, to hear bassist Mike Dirnt tell it, the pressure to record, release and promote the trilogy took an unexpected toll on the trio. "With hindsight 20/20 it was a tremendous undertaking," he told BBC Radio 1 host Zane Lowe. "Although we were having fun we didn't take our nose out of the book for a long time. I think it catches up with you a little bit ... I think it catches up with you a little bit. We definitely just jumped off a moving train."

In late September, Green Day announced that singer Billie Joe Armstrong was seeking help with unspecified substance issues.
 "Billie Joe is seeking treatment for substance abuse," read a statement on their Facebook page. "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."

Armstrong launched into a rant during Green Day's September 21 performance at iHeartRadio after being told that the band needed to wrap up their set, shouting "I'm not f---ing Justin Bieber, you motherf-----s. You've got to be f---ing joking ... I got one minute left." Green Day then smashed their instruments before departing the stage. And earlier that month, Green Day were also forced to cancel a concert in Italy after Armstrong was hospitalized. His bandmates would subsequently tell MTV News that he had "severe dehydration,"
 though he recovered in time to perform at the 2012 MTV Video Music Awards.

Dirnt said he and drummer Tré Cool were surprised by the rant and didn't see it coming.

"There were signs of things hitting the fan," he said. "We hadn't slept in forever and Billie had definitely had the worst of it. He'd been going through his own struggles ... We were there with him but you can only handle things on your own ... At the end of the day when we got off the road the most important thing was my friend's life."

Following Armstrong's hospitalization, the band canceled a series of promotional performances and on Monday they announced that they would have to pull out of a headline slot at the October 27 Voodoo Music + Arts Experience festival in New Orleans.

"Canceling shows is something we rarely do," Cool said in a statement announcing the canceled Voodoo gig. "We never want to let our fans down, and we are grateful for all of you being understanding during this time."

Stephen Rehage, founder/producer of Voodoo also hoped for the best in a statement on the cancellation. "We, like everyone, were looking forward to having Green Day back at Voodoo," he said. "Their 2004 performance was one of the festival's greatest. We are obviously disappointed in the news, but realize the health and well being of Billie Joe is the most important thing right now. We wish him and the entire Green Day family the best and offer them our full support."

Dirnt said he hasn't seen Armstrong for weeks, but he was confident things were going to be fine. "I'm sure Billie's had it really rough," she said. "There's been very little contact between us, so I guess I'm just generalizing, but it's a pretty heavy-duty process ... This is probably the longest time we haven't seen each other - I haven't seen Billie in weeks ... It's an awkward position to be in, but we're going to pander this out. We'll get there."

The band still plan to release the next album in the series, ¡Dos! on November 13.

As fans await news about the end of Armstrong's stint in rehab, they might have caught a glimpse of him Monday night when he made his pre-taped debut as a mentor
 on Christina Aguilera's team on "The Voice."