Britney Spears has cancelled two of her Las Vegas shows.

The 33-year-old singer injured herself when she slipped during a dance routine in her Piece of Me concert at Planet Hollywood Resort & Casino on Wednesday night.

Britney was belting out her famous hit (You Drive Me) Crazy when she jumped up into the air and landed awkwardly on her left ankle.

A video of the incident showed Britney grabbing her ankle in pain and grimacing.

However, as a testament to professionalism, the mother-of-two managed to continue singing throughout the incident.

Following her injury, Britney took to Twitter to reassure fans that she was doing well.

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

However it was later announced that Britney would be rescheduling her concerts on Friday and Saturday night to give her time to recover from the injury.

In a joint statement with Planet Hollywood and Live Nation, Britney "apologised for any inconvenience this causes ticket holders."

This is not the first time Britney's energetic dance routines have led to an injury.

Back in 2004, Britney was on her Onyx Hotel Tour when she suffered a knee injury on stage.

She had to reschedule two shows before injuring the limb once again a few months later ' leading to the cancellation of the remainder of her tour dates.

Britney has been performing to sold-out audiences at the AXIS auditorium in the Planet Hollywood resort since December 2013 - receiving an average $310,000 per show.