French perfomer Sarah Guyard-Guillot (31) plummeted into an open pit at the side of the stage after appearing to slip free of her safety wire.
Guyard-Guillot was being hoisted up in a harness for the final fight scene of the company’s ‘Ka’ show at the MGM Grand when the accident occurred.
Audience members at first thought the tragic fall was part of the show until loud screams were heard.
One shocked spectator Dan Mosqueda told how he heard screaming and groaning before a female artist began to sob on stage.
Immediately after the Paris-born acrobat’s fatal fall the show carried on before organisers brought it to a stop.
The death is the first as a result of an accident onstage in Cirque’s 30-year history.