Los Angeles: Britney Spears` manager has confirmed that the singer has been lip-syncing during her Las Vegas residency performances.
Adam Laber reportedly admitted that the former Disney star had difficulties singing all the songs in the setlist while she had to dance as well
"To put on the show that she puts on, it`s virtually impossible to sing the entire time and do what she does," Leber said.
"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," Leber added.
Spears` residency at Las Vegas`s Planet Hollywood is scheduled to run until 2015.