Guitar legend Carlos Santana passed out while performing a concert at the Pine Knob Music Theatre in Michigan on Tuesday night (local time).
Fans posted video and images of the incident in Clarkston to social media.
The collapse happened around 20 minutes into his set when he sat down on a drum riser to play the song Joy.
Santana was seen waving to fans as he was wheeled offstage by paramedics.
His manager has released a statement saying the collapse was the result of heat exhaustion and dehydration.
The guitarist is now "doing well" after being taken to hospital for observation.
The 74-year-old is best known to more recent music fans for his hit song Smooth released in 1999.
Santana has released 26 studio albums over his long career.