Updated

Las Vegas has a new pop fixture.

Britney Spears began her two-year residency at Planet Hollywood Resort & Casino on Friday night, just in time to catch the town's massive New Year's Eve crowds.

The audience stayed on its feet for the entire 90 minute show, dancing to airbrushed versions of the 32-year-old Spears' top hits, including "Toxic" and "I'm A Slave 4 U."

The young-for-Vegas crowd was there for the spectacle, which included acrobatics, a ring of fire, confetti, and a frequently airborne Spears.

The Grammy-winning singer will perform 50 shows each in 2014 and 2015. She is performing in a 7,000-seat theater that has been shrunken to 4,500 seats by closing the balcony.

Kurt Melien, who oversees entertainment programming for Planet Hollywood parent company Caesars Entertainment Corp., said Spears is using a recording of her voice to help her through the more physically grueling parts of the show, and add an electronic quality to her vocals. Some audience members said they thought they detected lip syncing.

A collection of pop stars, including Katy Perry and Miley Cyrus, attended the opening.

Spears is among the youngest stars to have settled down to quasi-retirement in Las Vegas. Other successful Strip headliners include Celine Dion and Elton John.

The show takes place in a relatively intimate theater with nightclub touches, including table and bottle service. Tickets range from $59 to $179.

Before the announcement of the residency, Spears' strongest Las Vegas tie derived from her short-lived marriage here. A 22-year-old Spears married her childhood friend in Sin City in 2004, and got the marriage annulled 55 hours later.

Spears made a grand Las Vegas entrance this month with fire-breathers, contortionists, snake charmers and hunky dancers welcoming her during a staged event at Planet Hollywood.

A portion of the Strip was temporarily closed so that she could pull up to the casino in a convertible. Spears told Las Vegas, "this is my city" now, then immediately went home to Los Angeles.

Spears has released seven platinum-plus albums since she debuted on the music scene in 1999. Her eighth album, "Britney Jean," was released this month to tepid reviews.