The pop star is set to make a whopping $310,000 per show at Planet Hollywood, but according to the New York Daily News, she'll be lip-syncing.
"Britney does not sing," a source says. "She is being paid a lot of money to lip-sync. She hasn't sung live for a couple of years."
The 31-year-old singer was also criticized for lip-syncing during her Circus tour, but a Britney source claims she's been in vocal training for months and is prepared to perform live.
"Britney will be singing," they tell GossipCop.
Do you think she'll actually be singing in Sin City or just faking it?