02/20/2014 11:13 EST | Updated 02/20/2014 11:59 EST

Oops, Britney Lip Syncs Again: Spears Caught Not Singing During Vegas Show (VIDEO)

Britney Spears definitely had an "oops" moment during her gig Tuesday night in Las Vegas. Well, either that or she's mastered the art of ventriloquism.

The Daily Mail reports Spears was acknowledging the crowd by waving after finishing one song. However a backing track for the ensuing tune "Alien" began while Spears kept walking with the microphone clearly far away from her mouth. As shown on a YouTube clip above, the opening lyrics "Cross through the universe to get..." can be heard before she puts the microphone back up to her lips.

News of the gaffe went on Instagram and Twitter with one user @samberato saying "#Britney forgets to sing #alien #pieceofme #vegas." Others tweeted about it also including this user:

The vocal error wasn't the first time it's happened to Spears. In fact, it happened just last week in Vegas. Not that everyone minds, considering this piece explaining why it's fine she's lip-syncing.

And then there was that famous incident in 2009 when a fan jumped on stage during a 2009 gig in Connecticut. As shown in another YouTube clip, Spears -- who was not injured in the incident but appeared initially frightened -- was shown screaming at the intruder while "Womanizer" continued to play on as if she was singing.

Regardless, Spears made no mention of the latest incident on her Twitter feed. Instead she thanked Nicole Richie who made a cameo during a portion of her concert earlier this week. Spears tweeted the following:

Spears will wrap up a portion of her Las Vegas residency this Saturday (Feb. 22) before taking a bit of a break. According to Planet Hollywood's site Spears will ramp up the show again in for a string of dates in late April and early May before another round of shows commences in mid-August.

Spears released her last studio album in November entitled "Britney Jean."

If you can't get enough of lip sync fails, we've compiled a bunch below, including the ne plus ultra of the art form by Ashlee Simpson as well as several more by Brit and a few we'd forgotten about.

Lip Sync Fails