UPDATE: The band shared an update on their website on Sunday, postponing an upcoming show and explaining that Kiedis was suffering from intestinal flu.
"Due to Anthony Kiedis' hospitalization from complications from the intestinal flu on Saturday evening, the Red Hot Chili Peppers regretfully must postpone their upcoming concert for iHeart Radio on May 17th," the band added. " They would like to extend their gratitude to the fans for the outpouring of well wishes. Anthony is expected to make a full recovery soon."
Red Hot Chili Pepper's frontman, Anthony Kiedis, was rushed to the hospital on Saturday ahead of the band's headlining spot on KROQ’s Weenie Roast Festival in Irvine, California.
The 53-year-old singer was reportedly rushed to the hospital with severe stomach pains, according to Billboard. KROQ, a local rock station in Los Angeles, let fans know about the cancellation via Twitter at 10:30 p.m. PT, roughly 30 minutes after the band was scheduled to take the stage.
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Kiedis' bandmates, bassist Flea, drummer Chad Smith, and guitarist Josh Klinghoffer took to the stage at Irvine Meadows Ampitheatre to apologize to the crowd of 16,000.
"Anthony is on the way to the hospital right now, and we're unable to play this evening," Flea said. "We are devastated about it. We're really sad. We love you so much. We live to rock."
"We live to f**king dig deep into the depths of our hearts and rock," he added, "but unfortunately, there’s a medical thing that happened, and he needed to deal with it."
Smith later took to Twitter to address fans as well. "NO one's more disappointed than us that we couldn't perform tonight," he wrote. "Sending love and a speedy recovery to my brother Anthony."
Weezer ended up closing out the festival, which also featured performances by Fitz and the Tantrums, Panic! at the Disco, Garbage and Cold War Kids.
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The rock band's next concert is scheduled for May 17 in Burbank, California, but there's no word yet on if they will perform.
ET reached out to RHCP's reps for comment, who had no further comment on Kiedis' health.