Lady Gaga is recovering in hospital after suffering from altitude sickness.
The Applause singer was admitted for medical care after falling ill following a concert in Denver, Colorado - where the elevation is one mile above sea level.
Gaga, 28, posted a selfie on Instagram which showed her in a hospital bed with an oxygen mask over her nose and mouth.
The Poker Face singer wrote: "Altitude Sickness is no Joke!
"#hitThatHospitalS**t #artRaveDenver many true ravers crowd tonight."
The star is currently on her ArtRave: The Artpop Ball tour.
Her next show, in Seattle, is expected to go ahead as planned.