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’.

Fully-formed: The 22-year-old woman told doctors she has had the nipple all her life. It measures almost two inches across, and doesn't cause her any pain

Fully-formed: The 22-year-old woman told doctors she has had the nipple all her life. It measures almost two inches across, and doesn’t cause her any pain

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.
Happy to bare all: Lily Allen proudly shows off her tiny third nipple, on her left breast

Happy to bare all: Lily Allen proudly shows off her tiny third nipple, on her left breast

Something in common: But while Mark Wahlberg, right, is proud of his third nipple, Zac Efron has denied claims he has two extra ones on his chest

Former Mark Wahlberg continued filming 'Ted' with Seth MacFarlane on Monday night. Mark Wahlberg continued filming 'Ted' with Seth MacFarlane on Monday night.