Photo by Evan Agostini/Invision/AP, file

A hip injury has prompted Lady Gaga to cancel the remaining dates on her "Born This Way" tour.

"After additional tests this morning to review the severity of the issue, it has been determined that Lady Gaga has a labral tear of the right hip," Gaga's booking company, Live Nation Global Touring, said in a news release Wednesday. "She will need surgery to repair the problem, followed by strict down time to recover. This, unfortunately, will force her to cancel the tour so she can heal."

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On Tuesday, the singer postponed four performance dates.

"I've been hiding a show injury and chronic pain for sometime now, over the past month it has worsened. I've been praying it would heal," the singer tweeted Tuesday. "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."

Refunds for canceled shows will be available beginning Thursday. There were 21 shows left in the tour.