Britney Spears' Las Vegas residency is now tainted with controversy as a recent technical malfunction has puts doubts that the singer might be lip syncing this whole time.

A video posted on Instagram showed the “Perfume” singer with her mic falling off her waistband and pulling the device away from her mouth as she was belting out “Stronger.”

While the singer maintained her poise and kept her choreography (she even managed a 360 spin), viewers and netizens were quick to point out that the quality of her vocals didn't seem to change a bit, according to Radar Online.

E! noted that it's not the first time Britney Spears; Las Vegas live show suffered a technical malfunction when her corset flew open and revealing that the star might not be wearing any bra.

During the opening of her Las Vegas Residency, fans also reportedly noticed that Britney Speared to have lip synced some of the songs, MailOnline.

However, it just looked that she was lip syncing, explained Kurt Melien, entertainment programming at Caesars Entertainment Corp., because Britney Spears performed against the recorded track “to help her through the more physically gruelling parts of the set,” according to the report by CBS News.

He also said that many of Britney Spears' songs also feature the electronic undertones that become almost a Britney staple which might appear lip-syncing but she sang the entire set.

Meilen's statements was also supported by Britney Spears' manager, Larry Rudolph, who told Radar: “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.”

Britney Spears' show requires her to go through seven costume changes and two wig changes as she performs 23 of her greatest hits.

The singer will lead her audience to a nostalgic tour to her successful career as she performs “Oops ... I Did It Again” or “Baby One More Time.” She also performed “Circus,” “Toxic,” “Lucky,” and “Work Bitch.”