Billboard reports:

Green Day has announced the cancellation of seven tour dates and the postponement of 21 more, following last month's announcement that frontman Billie Joe Armstrong is in treatment for substance abuse.

All of the trio's remaining 2012 tour dates, which included a West Coast run through late November and early December, have been cancelled. Green Day had announced earlier this month that it would not be performing at the Voodoo Festival in New Orleans, which took place last Saturday (Oct. 27).

In addition, the North American leg of Green Day's 21-date 2013 tour, set to kick off in Green Bay on Jan. 7, has been postponed. The dates had been announced in mid-September in support of the group's new trio of albums, "Uno!," "Dos!" and "Tre!" 

"Obviously the timing for this isn't ideal, but Billie Joe's well-being is our main concern," says bassist  Mike Dirnt in a press statement.  "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."

Green Day has also bumped up the release of "Tre!," from Jan. 15, 2013 to Dec. 11. "Uno!" was released in September, while "Dos!" is coming on Nov. 13.

"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," says drummer Tré Cool.  "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 band announced that Armstrong would be seeking treatment for substance abuse last month, after the 40-year-old frontman had a profanity-filled onstage meltdown at the iHeartRadio Music Festival in Las Vegas. Days later, "Uno!" was released, and sold 139,000 copies in its first week according to Nielsen SoundScan, good for a No. 2 debut on the Billboard 200.

Along with "Dos!" and "Tre!," Green Day has a new song, "The Forgotten," coming out on the "Twilight Saga: Breaking Dawn - Part 2" soundtrack, also hitting stores on Nov. 13. "Stray Heart," the first single from "Dos!," is out now