The Royal Mint is to give a "lucky" silver penny to babies born on the same day as the Duke and Duchess of Cambridge's first child.
More than 2,013 commemorative coins have been created to give to babies who share a birthday with the third in line to the throne.
Prince William hopes to be present for the birth, expected in mid-July, if his RAF duties allow.
The 1p silver coin has been stamped with the year 2013 and is worth £28.
The penny, which will be presented in a pink or blue pouch, features a shield of the Royal Arms, which can be seen in its entirety on the £1 coin.
Designer Matthew Dent chose the Royal Arms shield because it was in keeping with "the basis of coinage design in Britain for hundreds of years".
Shane Bissett, director of commemorative coins at the Royal Mint, said: "The birth of the royal baby will be a joyous occasion not just for Their Royal Highnesses the Duke and Duchess of Cambridge but also for the whole nation, as we prepare to celebrate another remarkable milestone in their life journey together.
"However, it will also be a special day for many mothers and fathers across the country as they too welcome the arrival of their new baby, hence why we wanted to extend this historical moment to them with a lucky silver penny".
According to traditional folklore, crossing the palm of a new born baby with silver or offering them a silver penny is a way of wishing them a wealthy and healthy life.
The commemorative penny follows special coins released by the Royal Mint for the Royal couple's engagement and wedding.
Parents of newborns who share their birthday with the Royal baby will need to apply online for one of the coins by visiting Facebook.com/theroyalmint.
They will have 60 days to register for the coin from the birth date, and have to provide a copy of their child's birth certificate to qualify.