Lady Gaga has canceled the rest of her tour dates due to a hip injury.

Live Nation Global Touring said in a news release Wednesday that Lady Gaga has a tear in her right hip that will require surgery, followed by a recovery period.

The pop star's website showed 21 dates through March 20 remaining on her "Born This Way Ball" tour schedule. Fans who have already bought tickets will receive a refund beginning Thursday.

Lady Gaga postponed four dates on Tuesday after experiencing difficulties Monday during her concert in Montreal. The singer's show is high energy with non-stop dancing. She explained to fans on Twitter that she'd hurt herself while performing some time ago.
She wrote: "I hid it from my staff, I didn't want to disappoint my amazing fans. However after last nights performance I could not walk and still can't".

A news release announcing postponements Tuesday said the 26-year-old singer, whose real name is Stefani Germanotta, was suffering from synovitis, an inflammation of the joints. She underwent tests Wednesday morning that showed she had a labral tear in her right hip, however. The labrum is a layer of muscle that helps holds the ball-shaped hip joint in place. The news release says the surgery will require strict downtime.