Billie Joe Armstrong of Green Day (QMI Agency file photo) Billie Joe Armstrong bounces back

Green Day star Mike Dirnt has opened up about frontman Billie Joe Armstrong's recent health scare, revealing his bandmate was hospitalized after a bad bout of influenza.

The rockers had to call off a gig in Italy on Sunday night after Armstrong fell ill with a mystery ailment while in Bologna.

Now bassist Dirnt has revealed Armstrong was struck down with severe dehydration and a case of flu, which left him "vomiting profusely".

He tells MTV News, "Billie came down with heavy, heavy dehydration; it was like severe dehydration, influenza, and it was just a really, really bad situation. He woke up in the morning and it was bad. Let's put it this way, if you're in your hotel room and you're vomiting profusely, it's not fun. So what are you gonna do? It's hard to sing while you're puking."

Dirnt also assured Italian fans the Basket Case hitmakers will reschedule their axed concert as soon as possible.

He adds, "We're going to make our way back to Bologna and play that show ASAP. We don't miss many shows; we've maybe missed five shows out of our entire career and we pride ourselves on that, but we're human."

Armstrong is expected to make his stage comeback when Green Day performs at MTV's Video Music Awards in Los Angeles on Thursday.