She took to social networking site Twitter earlier this evening (May 10) and explained that the choreography and performances she gives on the Born This Way Ball are so exhausting that she often throws up during shows:

"Yes Tokyo! Tonight was the first BTWBall that I didn't puke during show. (yes its that hard) xoxoxxxo Love, gaga+terry"

She later added another message and shared a photograph of herself with photographer Terry Richardson: "Tonight was happiness, joy, gratitude. I'm the lucky one Japan. You are so special."

Gaga will perform at Tokyo's Saitama Super Arena on May 12 and 13.