Cher is back and larger than life with an all-new, exciting Vegas show -- and ET's Mark Steines is getting the grand tour behind the scenes with the ageless diva! But first, she's clearing the air on tabloid rumors about her health…

"I don't look at them, so I don't know," says Cher about the tabloids and reports that she is battling cancer and seeing Farrah Fawcett's doctor for treatment of the disease. She shrugs off the rumors, saying that her health is okay.

"Yeah!" she tells Mark. "What did it look like tonight [when I was performing]?"

Cher has had her share of setbacks with the show. She previously had to cancel her run in Vegas prematurely due to asthma problems, and in order to preserve her voice, she does not speak at all when she's not on stage.

"After the show I just do complete vocal rest," she says. "I text my friends, which aggravates them to death, or I e-mail them, and I just write notes to whoever's around."

And sometimes performing live presents its own hazards: "I've fallen twice on that stage!" she reveals, explaining that during the "If I Could Turn Back Time" number, dancers throw their hats and, "My right foot hit [a] cowboy hat and felt like Superman. … And then I fell on my knee and my hands -- [but] I never dropped the microphone. I never missed a beat, didn't miss a note or word, and I think [the audience was] just stunned that I fell so hardcore and then just jumped up; because I was [stunned]."

Cher's show at The Colosseum at Caesars Palace is an ultra-glitzy, 90-minute production spectacular that leaves audiences breathless and wanting more, performing her hits from across the decades backed by breathtaking choreography and all the Vegas-style trimmings.

"My voice is The Picture of Dorian Gray," she says about her timeless vocal ability, which seems to get better with age. "Who thought I would be here this long? No one."

And Cher pulls no punches when it comes to the Octuplet Mom, Nadya Suleman, saying, "You cannot be a single mom living with your parents on welfare and have all of those children. That chick is like on planet I-don't-know-where."

Watch ET for more with Cher!