Lady Gaga had ordered the emergency services to set up oxygen cylinders for her latest 'Jingle Bell Ball' performance at London's O2 Arena.
It has been revealed that oxygen helps the 27-year-old singer de-stress and feel calm and energetic, the Mirror reported.
Sources have revealed that the 27-year-old singer had oxygen with her during her last tour and that she relies on the oxygen supply in work situations.
The source added that as Gaga has had a rough year, she considers oxygen as an essential medical supply.
