Green Day was on Metallica's mind as the headbangers filled in for their San Francisco Bay Area mates over the weekend at New Orleans' Voodoo Music + Arts Experience.

"We're Green Day, just a little taller," Metallica frontman James Hetfield told the crowd early in his band's two-hour set on Saturday (October 27), which filled the slot Green Day bowed out of after frontman Billie Joe Armstrong checked into rehab in September.

The group dedicated its song "Battery" to Armstrong, and at the start of Saturday's encore Hetfield noted that Green Day is "getting it sorted out. Hopefully they get it fixed, because the world needs them" -- and followed with the opening riff of Green Day's "American Idiot."

After releasing "Uno!" in September, Green Day will be releasing "Dos!" on November 13. "Tre!" was scheduled to follow on January 15, though the date has now been moved up to December 11.

The group was slated to begin a North American tour on November 25 in Seattle, but has since canceled their remaining 2012 appearances, with dates for 2013 in January and February expected to be postponed.

Metallica, meanwhile, will be releasing a new DVD, "Quebec Magnetic," on December 10 and is finishing work on a 3D film it plans to release during the summer of 2013.

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