Britney Spears has to have an operation after hurting her knee while making a video, her record company confirmed.
The singer was taken for a scan after she fell over and that showed a piece of cartilage floating in her knee.
Cartilage joins bone and muscle together, so doctors need to operate to sort it all out.
She was filming a video for her new single Outrageous with rapper Snoop Dogg. The single is going to be one of the songs on the new Catwoman film.