Poor Lady Gaga was hospitalized after her concert in Denver.
The singer shared a selfie on Instagram that shows her in an oxygen mask with the caption, "Altitude Sickness is no Joke! #hitThatHospitalS--t #artRaveDenver many true ravers crowd tonight."
Gaga’s next stop on the artRave tour is in Seattle on Friday. So far, there have been no plans to cancel the show.
Lady Gaga was forced to cancel a series of concerts last year following hip surgery.