The reality TV star had the scan to show critics she has not had silicone implants in her cheeks.
Egged on by her sisters, cameras were rolling as the 30-year-old brunette chatted to the family doctor and lay down on an x-ray table in his office.
She said: “Today I am gong to have a butt x-ray to prove to the world it’s real. This is a really crazy request but my sisters have dared me to get an ass x-ray because of all the rumours it’s not real. If I were to have a fake ass, wouldn’t it be dimple free?”
Kim was persuaded to go for a bum scan after reading stories about her curves on celebrity blogs.
The curvaceous star laughed as older sister Kourtney read one tale aloud, which claimed one of her “butt cheeks” had exploded during a flight from New Jersey to Las Vegas.
Kim said: “I can’t even take this seriously ... Who the hell of a normal person gets butt implants?”