Los Angeles - Lady Gaga insisted on being fully naked for a new video, despite being given a white nurse's uniform to wear.
Serbian performance artist Marina Abramovic provided the 27-year-old singer with the garment to cover her modesty for a scene in the Abramovic Method clip - in which she had to walk around in woods for three hours while blindfolded until she found her way home - but she instinctively chose to bare all instead.
Marina said: "The idea was that artists, even blindfolded, have to have vision like a blind man.
"To feel with their entire body (...) She was in the fields and then the forest and by her pure intuition she had to find her way back home (...) During this exercise, completely of her own initiative, she took off her clothes. She just wanted to be in nature and to feel the elements."
'She is a hardcore student'
Gaga was attacked by spiders and angry mosquitos during her nude scenes, and Marina - who is known for her endurance-testing works - was concerned the Born This Way hitmaker might get Lyme disease from all the ticks in the area.
She added to MTV News: "She is a hardcore student. I had to blindfold her and she was in the forest for three hours, eaten by mosquitos and spiders, scratched by the bushes. It was quite incredible.
"Whatever I told her she met the exercise absolutely to the end, never complaining. And my exercises are pretty tough.
"She never said it was too much, she said, 'I want more,' every time."
Gaga's video is part of a Kickstarter campaign to raise money for the Marina Abramovic Institute, a $20m living museum in Hudson, New York.
Marina is attempting to raise $600 000 through the donation service to fund her artworks. So far she has $250 000 of her target.
Watch the very strange video below. Warning: The video contains full frontal nudity and is NSFW.