Guitarist Joe Perry staggered offstage and reportedly had a medical emergency in New York on Sunday night.
Bandmate Alice Cooper reportedly told the crowd that Perry had been "very sick" before the concert. He and fellow bandmate Johnny Depp continued with the show as Perry was taken to a local hospital.
A tweet from Perry's twitter account thanked people for their concern, saying, "Thanks to all of the fans reaching out and asking about Joe. He is stable right now, with family and is under the best care."
It's unclear whether Perry will be well enough to perform at Hollywood Vampires' next concert in Ohio on Tuesday.
This video includes clips from Columbia Records / Aerosmith, Billboard, WGBH, YouTube, Joe Perry and Facebook / The Hollywood Vampires, and images from Getty Images. Music provided courtesy of APM Music.