Britney Spears and her manager said she would not be lip-syncing during her "Piece of Me" show at the Planet Hollywood Resort & Casino in Las Vegas, but the singer has reportedly been caught several times.
The most recent incident happened last night when she was singing “Perfume,” but pop singer Sia’s voice was actually heard by the audience, reports RadarOnline.com.
Sia, who co-wrote the song, was featured on an acoustic version of “Perfume” in a January release.
RadarOnline.com notes that audience members, who are paying big bucks, have been disappointed in Spears' lip-syncing and dance moves during recent shows.
In response to complaints, Spears’ manager Adam Leber told RadarOnline.com in June, "To put on the show that she puts on, it’s virtually impossible to sing the entire time and do what she does. She’s singing on every song, basically, when she has the ability to sing. There’s no way you can dance for 90 minutes straight and sing the entire time.”
However, Tina Turner and Bruce Springsteen (among others) have put on far longer shows than 90 minutes without lip-syncing.
"I'm definitely going to be singing live," Spears told 103KissFM.com in 2013, noted The Huffington Post. "I always sing live. It doesn't sound so great all the time, but I do my best."
Spears' manager Larry Rudolph told Billboard in 2013, "She's going to be singing live. She does choreography and vocal coaching every day. The vocal coaching is really just to strengthen her voice and get her to a point where she can go out there every night and do a full show."
"It's hard for the public to fully understand what goes on when you get on stage and you're dancing full out during a song," added Rudolph. "No matter what anyone says, there's not a single artist who goes out there and does full choreography and is singing without a vocal track underneath them at the same time. It's physically impossible."
"We're just trying to build up her stamina and get her to a point where she can do as much as humanly possible. The idea is to try to get her pretty close to 100%. There might be some numbers where she's full out dancing with a (vocal) track underneath her, but there won't be any lip-syncing across the board on anything."
However, there was no mention of Spears' voice being replaced by another singer's pre-recorded voice.