Billie Joe Armstrong and Rosie Perez to Guest Star on Nurse Jackie

The diagnosis for Nurse Jackie season four guest stars is in, and all signs are positive.

Showtime announced today that Green Day frontman Bille Joe Armstrong and veteran actress Rosie Perez will both come on board the series in 2012. The latter will portray a patient named Jules, while it's unknown what role the singer will take on.

But in case you require proof of the casting, Executive Producer Richie Jackson Tweeted out this photo from a day on set during the shooting of the fourth season premiere: