Pop star Britney Spears faced a wardrobe malfunction on stage Saturday, Dec. 28 when her dress completely opened in the back due to a faulty zipper.

The 32-year-old was onstage performing Circus in Las Vegas' Planet Hollywood Hotel and Casino, part of her two-year residency show there, when the back of her tight, sequin dress flew open unexpectedly. A fan Instagram video captured the moment and the look of panic on Spears' face as she realized she was close to flashing her audience.

Staying professional, she continued on with her choreography despite her looming wardrobe malfunction. A backup dancer then zipped her dress back up, though he looked like he had difficulty pulling up the zipper. The Piece of Me show then carried on with no future problems.

The Instagram user captioned the video, " Circus when her dress almost came off #britneyspears#britneyspearsconcert#vegas#lasvegas#dressmalgunction#singer#whathappensinvegasstaysinvegas." 

See the video below capturing the wardrobe malfunction.

Spears kicked off her Piece of Me show on Friday, Dec. 27. Many A-listers were in the audience for opening night, including Miley Cyrus, Katy Perry, Selena Gomez and Adam Lambert. Cyrus stood front row and a video caught her dancing and singing along as Spears performed Till The World Ends. In another clip, the 21-year-old danced with Spears' backup performers and even appeared to kiss one. 

Spears expressed her gratitude for Cyrus' attendance and tweeted, "@MileyCyrus Love you so much! Thank you for coming to #PieceOfMe! I adore you :)." 

See performance videos from Spears' first Las Vegas show here.

Tags: Britney Spears