Green Day's Billie Joe Armstrong Is Coming to Nurse Jackie!

Executive producer calls Green Day frontman a "new cast member" and tweets out photo of rocker with star Edie Falco

Looks like Peter Facinelli's Dr. "Coop" Cooper isn't the biggest celebrity at All Saints anymore!

Showtime confirms that Green Day frontman Billie Joe Armstrong will be guest starring on the series' upcoming fourth season, which is now in production.

So will the rocker be playing himself?

Nope!

No futher details yet, but it appears Billie is partnering up with Edie Falco for at least one scene in the fourth-season premiere. Executive producer Richie Jackson tweeted out an on-set photo of the two, saying,  "Edie and our new cast member @BJAOfficial! Wait til you see the season premiere!"

Hmmm..."cast member?" Could this mean Billie will be doing much more than one episode?

Coop, buddy, you better up your game if you want to keep your status as the hospital's "It" boy. Or maybe try a little guyliner? Wouldn't hurt!

—Additional reporting by Drusilla Moorhouse and Marc Malkin