Britney Spears cancels shows after onstage fall

"Britney injured her ankle during her performance Wednesday evening and her doctor has advised her not to perform Friday and Saturday evening so that she may heal," said a statement.

A video posted by the TMZ celebrity website showed her tumble while surrounded by backing dancers, clutching her ankle before being helped back to her feet.

"Sorry about that," she told the audience, before apparently resuming her performance for the next song, albeit with a slight limp.

She later tweeted: "Thank you for all of the sweet wishes! Had a little scare on stage tonight with my ankle but I’m ok!"

The former enfant terrible of US pop opened a two-year sojourn at Sin City's Planet Hollywood Resort & Casino in December 2013. The Grammy winner was hired to perform her show, "Piece of Me," 50 times a year in 2014 and 2015.

Spears was on the front pages of celebrity magazines -- and eventually scandal supermarket tabloids -- during much of her career.

Those scandals are in the past, although her future as the Princess of Pop was thrown into fresh doubt when her last album, "Britney Jean," received only lukewarm reviews.

Spears has joined a panoply of music stars who have taken time out for temporary residence in Las Vegas, including Elton John, Shania Twain, Rod Stewart and Celine Dion.

Ticket holders can get refunds or exchanges.