"We're taped and all set," an NBC representative said. Armstrong recorded his stints earlier this summer as a mentor on Christina Aguilera's team.
The Green Day frontman is currently seeking treatment for substance abuse after an onstage meltdown at the iHeartRadio Music Festival in Las Vegas, where he smashed a guitar and engaged in a profanity-riddled rant accusing organizers of cutting the band's set short.
In a post on Facebook yesterday, Green Day apologized to fans and festival organizers and announced they will postpone come upcoming apeparances while Armstrong seeks help. The band's new record, ¡Uno!, is out tomorrow.