Woman, 22, grows full-sized nipple on the sole of her FOOT

Lily Allen proudly showed hers off on television, Mark Wahlberg's famous for his and just last week, Zac Efron was forced to deny he has two.

But a 22-year-old woman has trumped them all - by growing a full-sized extra nipple on the sole of her foot.

Although one in 50 women and one in 100 men have extra nipples, according to the California-based Dermatology Journal it's the first time one has ever been discovered so far down somebody's body.

Unique: Extra nipples are usually found above the bellybutton, and doctors say it's the first time they have ever seen one on somebody's foot

The woman told doctors she had had the unusual growth - which is almost two inches wide - all her life, and it had never caused her any pain.

Between one and five per cent of the population have the condition, known as supernumerary breast tissue.

Although most of the time extra nipples are found along the milk lines, which run from the genitals to the armpits, they have been discovered on the back, thigh or even the face - but never the feet.

Mark Wahlberg has a third nipple just below his left one. The former Calvin Klein model considered having it removed but then changed his mind, calling it his most 'prized possession'.

Last week dermatologist Dr Katherine Rothman said she believed Zac Efron had not one but two extra nipples, below his normal ones on his chest.

His spokesman denied the claims, but it prompted new interest in the topic - and the rediscovery of the 22-year-old woman's case, which was first published in Dermatology Journal in 2006.

According to researchers in Brazil: 'A 22-year-old woman sought medical care for a lesion in the plantar region of her left foot, a well-formed nipple surrounded by areola and hair.

'Microscopic examination of the dermis showed hair follicles, eccrine glands, and sebaceous glands.'

There are eight categories of supernumerary nipple. They range from polythelia pilosa, which is just a patch of hair, and develop up to a complete nipple with glandular tissue and areola.

Researchers classified this case as stage five, which means it has a nipple and areola but no fat tissue.

Third nipples have been mentioned throughout history and folklore, and were once known as 'witch's nipples'.

Anne Boleyn, one of Henry VIII's wives, was rumored to have not only a third nipple but also a third breast - causing some to brand her a witch.