Green Day front man and Broadway veteran Billie Joe Armstrong was hospitalized over the weekend, forcing the group to cancel a concert in Bologna, Italy, according to People Magazine.
The singer was hospitalized due to illness according to bassist Mike Dirnt, but the illness was not disclosed. The band's next scheduled show is in Las Vegas on September 21.
With Dirnt and drummer Tre Cool, Armstrong wrote the music for the successful album American Idiot, which was later turned into a stage musical. Armstrong appeared in the Broadway production as the character St. Jimmy.