We knew Lady Gaga was on fire, but damn.

The pop starlet has postponed four upcoming shows on her Born This Way Ball Tour after being diagnosed with synovitis, a severe inflammation of the joints. "I hid it from my staff, I didn't want to disappoint my amazing fans," Gaga tweeted today. "However after last night's performance, I could not walk and still can't."

"It will hopefully heal as soon as possible, I hate this," she continued. "I love you and I'm sorry."

Gaga has cancelled her upcoming performances at the United Center in Chicago (Feb. 13 and 14); at the Palace of Auburn Hills in Detroit (Feb. 16); and at the Copps Coliseum in Hamilton (Feb. 17). The shows will be rescheduled, according to her website. The rest of the tour is expected to proceed as scheduled.

[via SPIN]