LONDON -

If you're born on the same day as the future king or queen of England, you don't have to worry very much about people forgetting your birthday. And now the first 2,013 lucky British babies born on the same day that Kate Middleton gives birth to the third in line to the throne will also get a unique keepsake: a lucky, silver penny.

Britain's Royal Mint will give away the commemorative one pence pieces - which are usually copper - to mark the birth of one of the world's most anticipated babies in decades. The Duchess of Cambridge, as Middleton is now known, is due in the next week or two.

The penny is decorated with the baby's great grandmother - Queen Elizabeth II - on one side and a shield from the Royal Arms, the Queen's official coat of arms, on the other.

In Britain giving silver to mark a birth is good luck. Offering a silver penny or putting something silver into the baby's palm is a way to wish them wealth and good health.

"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," says Shane Bissett, director of commemorative coin at the Royal Mint. "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."

The Duchess' baby will inspire a $300 million spending spree in the United Kingdom, according to economists, including $120 million on merchandise alone.

Fisher Price created a range of prince and princess themed potties that play Royal musical tunes. Tesco, Britain's largest retailer, is offering T-shirts with the words "Born to be Royal." Krispy Kreme is selling limited edition doughnuts with blue or pink centers. Even Buckingham Palace is getting in on the act, selling onesies decorated like a Palace guard's uniform for about $20.

The penny is not minted for the occasion, according to Royal Mint spokeswoman Kate Fitzpatrick. Every year the Mint sells 10,000 silver pennies for about $45 each. What's special about this one is that it will be given away to mothers who give birth on the same day at the Duchess of Cambridge, and it will come with commemorative blue or pink pouches.

Kate and William are the most popular members of the Royal family. The Mint has already taken advantage of the huge level of interest in the couple in the past, selling 250,000 coins created for their wedding day.

The offer is only available to British parents. No Americans can apply.