Sarah Guillot-Guyard was performing in Ka at the MGM Grand when she fell from her safety wire during a high-flying scene and plummeted into a pit below the stage.
The 31 year old was taken to hospital, where she was pronounced dead, and a number of Cirque Du Soleil fans have taken to Twitter.com to offer their condolences.
How I Met Your Mother actor Harris writes, "My thoughts go out to the family of Sarah Guyard-Guillot, an amazing performer in Ka who died last night. Original cast member. So sad."
Judd, who was watching another Cirque production shortly before she heard the news, also tweeted, "Saw Quidam Show, Cirque du Soleil: exquisite. The artists are mind boggling, every aspect of production is so inventive. We were delighted. And in real time hear tragic news of Sarah Guyard-Guillot death in a Cirque show elsewhere; heartfelt condolences to her children & family."
Vampire Diaries star Nina Dobrev adds, "Shocked and saddened by the news of Cirque Du Soleil performer Sarah... Guyard's death. My condolences go to her family."