Sarah Guillot-Guyard, 31, was supposed to be attached to a safety wire while acting out a battle scene high up on a wall -- suspended by wires -- during a performance of "Ka" at the MGM Grand. But something went wrong, and she went plunging into an unseen pit below the performers.
"She was screaming as she was falling down, and it was sort of out of a movie where she was trying to grab for anything," said one audience member.
The show momentarily continued, then stopped. Minutes after the accident, a recorded announcement informed audience members that refunds or vouchers to future shows would be offered, and the crowd was dismissed.
Coroner's officials said Guillot-Guyard was pronounced dead at a hospital late Saturday night after falling about 50 feet.
"I am heartbroken," Cirque du Soleil founder Guy Laliberte said in a statement. "We are reminded with great humility and respect how extraordinary our artists are each and every night. Our focus now is to support each other as a family."
The death was the first stage casualty in the company's 29-year history, according to Cirque spokeswoman Renee-Claude Menard.
It was unclear how the accident happened. Menard said Guillot-Guyard didn't slip out of her harness, but couldn't provide additional information about the incident.
Guillot-Guyard, a mother of two, had been with the original cast of "Ka" since 2006, and had been an acrobatic performer for more than 20 years, according to Cirque officials. Born in Paris, she is also listed as the head coach at Cirquefit, a program that offers acrobatic fitness classes for children.
No reopening date has been set for "Ka."
The Associated Press contributed to this report.