Why Lady Gaga postponed her next four concerts

Lady Gaga tweeted her fans with disappointing news: The next four concerts in her "Born This Way Ball" tour will be rescheduled for an unknown future date.

Lady Gaga, seen here at Newark's Prudential Center in December, announced today that she's taking a few days off from performing.

Evan Agostini / Invision / AP / File

February 12, 2013

Lady Gaga says she's "heartsick" to postpone four shows after sustaining an injury that's left her unable to walk.

A Tuesday news release says performances set for Feb. 13-14 in Chicago, Feb. 16 in Detroit and Feb. 17 in Hamilton, Ontario, Canada, have been postponed.

Gaga took to Twitter to explain, saying she injured herself during a performance some time ago and her condition has worsened, leaving her immobile following Monday's concert in Montreal. She's been hiding the injury from her staff, but can no longer perform.

In Kentucky, the oldest Black independent library is still making history

"I've been hiding a show injury and chronic pain for sometime now, over the last month it has worsened," she wrote. "I've been praying it would heal".

Neither Lady Gaga nor the news release specifies what the injury is. The remainder of the "Born This Way Ball" tour is expected to continue on schedule, beginning with a two-night stand in Philadelphia on Feb. 19-20. Makeup dates for the missed shows will be announced later.