Bassist Flea broke the news to concert-goers about his 53-year-old bandmate's hospitalization and apologized on behalf of the band telling the crowd at the venue that they were "devastated," reported Billboard.
According to a representative for the Los Angeles radio station, Kiedis was taken from the venue in an ambulance suffering from extreme stomach pain. The exact nature of the problem is unknown at this time.
Weezer ended up closing the show, which was held in Irvine, California.
Other bands on the bill included Panic! at the Disco, Empire of the Sun, Garbage, The Lumineers, Fitz and the Tantrums and Miike Snow.