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Green Day Singer Billie Joe Armstrong Has The Greatest Summer Job Ever

You know, just hanging out with his heroes. No biggie.

Billie Joe Armstrong isn't the kind of dude who just sits around on the couch all summer watching soccer and baseball. No, the Green Day singer can't sit still, which explains why during a break between his band's touring and recording he's scored the coolest summer job ever: rhythm guitarist for the reunited Replacements.

Starting with surprise appearance at Coachella in April where BJA helped the legendary 1980s Minneapolis shamble punk icons out by assisting ailing 'Mats singer Paul Westerberg (who was laid low by persistent back problems), Billie has seemingly joined on as an unofficial fifth Replacement. (He also played with them at the Shaky Knees Festival in Atlanta in May.)

And, there he was again on Sunday at Louisville's Forecastle Festival, playing rhythm guitar while wearing a blue and black striped blazer, black jeans and a grin a mile wide. It was one of those, "Wait, is that?..." moments for many in the crowd (including yours truly), as the giant screens on either side of the main stage showed a familiar-looking guy with jet black hair strumming away on such classic tunes as "I'll Be You," "Favorite Thing," "Achin' To Be," Androgynous" and "Bastards of Young."

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And the cool thing? Billie was just there. Nobody mentioned him, he didn't sing back-up vocals and seemed happy to just hang out and let Westerberg and guitarist Dave Minehan do the heavy riff lifting. In fact, at one point Westerberg's mic slipped down on its stand and the singer strained to bend over and sing into it. Billie Joe came over, playfully adjusted it up and down, then locked it in its proper place and planted a big kiss on Westerberg's lips.

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When Westerberg trashed one of his guitars, roadie Joe ran out to retrieve it and set it aside, prompting Westerberg to make the only reference to their special guest during the entire 80-minute set. "Billie Joe's gonna put that on Ebay," Westerberg joked. "No reserve," Billie shot back with a smile.

Playing with your heroes is one thing, but having them end the set with a song just for you?: priceless. And that's how the 'Mats capped it off, playing a special version of "I Don't Know" at Billie's request.

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Best summer job. Ever.