A student doesn't get hangovers like her friends at university because she double the number of kidneys most people have.
Jessica Curphey, 20, stunned doctors when she was rushed to hospital in Surrey after developing a sharp pain on her right side.
Scans by staff at St Helier Hospital revealed what looked like a huge cyst growing inside Curphey's body, who studies at Surrey's University of Creative Arts.
Doctors opted to carry out an operation, which was when the real issue was discovered. The terrible pain was a rupture in one of her extra kidneys.
Then medical staff got a second and even bigger shock, when they uncovered yet another kidney inside Curphey's torso.
Both were damaged, so it was decided to remove them and the student from Manchester spent five months in hospital.
It is estimated that fewer than 100 other people on the planet have extra organs. Experts called the condition exceptionally rare.
A GP had misdiagnosed Curphey's pain as a urine infection and prescribed her antibiotics.
Curphey said: "It's quite fun watching how people react when you tell them that you've got an extra kidney.
"I suppose it's weird not knowing what's going on inside your body until something happens like with me.
"On the upside, I don't get as bad hangovers like my friends - perhaps down to my extra kidneys."
Kidneys play a vital role in cleaning the blood by absorbing all sorts of potentially toxic substances - including alcohol.
Curphey's story was revealed as part of her fundraising drive for Kidney Research UK.
Professor Neil Turner, medical spokesperson for Kidney Research UK, said: "Development of the kidneys is pretty complex and there are all kinds of varieties. Doubling of the kidneys on each side can happen, and partial doubling is quite common, while complete doubling to form completely separate kidneys is rare.
Many people have these variations without knowing about it, and it doesn't usually affect kidney function for better or worse."