Pop star Britney Spears fell on stage during a performance in Las Vegas Wednesday, but later assured fans she was fine.

A YouTube video that surfaced at about 3 a.m. Thursday, shot from close to the stage at the Axis Theater in the Planet Hollywood hotel and casino, shows Spears, 33, stumbling while singing and dancing to "(You Drive Me) Crazy."

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Continuing to perform without pause, she remains seated for several seconds before starting to get up. Two dancers help her to her feet, and, seconds later, after the song ends, she tells the applauding audience, "All righty, then! Sorry about that!"

Afterward she tweeted, "Thank you for all of the sweet wishes! Had a little scare on stage tonight with my ankle but I'm ok!"