Green Day Resurrect John Lennon for 'Idol'

Speaking of irony, Green Day went from 'American Idiot' to 'American Idol' Wednesday night with a surprise -- though widely rumored -- performance on the latter's season finale. While the punk vets' appearance seems to negate their anti-capitalism sentiments, Billie Joe and Co. will do whatever the hell they want, thank you very much. Especially if it means abandoning their proverbial soap box for a good cause.

Green Day rocked 'Idol' something fierce with their take on John Lennon's 'Working Class Hero,' a cut from the forthcoming double-disc 'Instant Karma: The Amnesty International Campaign to Save Darfur' -- which features all Lennon covers by heavyweight artists including U2, R.E.M. and the Flaming Lips, among others -- in effort to raise money and awareness for the conflict-riddled Sudan region.

"We wanted to do 'Working Class Hero' because its themes of alienation, class and social status really resonated with us," Green Day frontman Billie Joe Armstrong said.

Fans can purchase the band's cover on iTunes now, while the entire 'Instant Karma' collection hits shelves on June 12.