Britain’s retailers might just be rejoicing as much as Kate and Wills about the birth of a new baby princess.

Baby boutiques, clothing stores and fashion designers received a gift that will keep on giving when the Duchess of Cambridge gave birth to a girl, and all the marketing opportunities she provides, instead of another boring boy, retail experts say. From christening gown to wedding dress, and all the hairstyles in between, every trend the newest royal sets will be fodder for girls seeking to emulate a real life princess.

"The royals having a baby girl is most likely to result in a financial windfall for everyone, U.K. tourism and retailers alike," said Tonya Williams Bradford, a marketing expert at the University of Notre Dame in Indiana.

"Unlike with the birth of their beautiful baby boy, where the attention turns to whose next on the throne, this baby girl will provide many style opportunities, as her mother and the late Lady Diana did before her." 

Consumers rush to buy all things royal because they are famous in a non-Kardashian way: internationally known but above celebrity. People want to copy what the former Kate Middleton and Prince William and now their children are wearing, to touch a bit of that distant gilded glow.

"People, particularly Americans, love it," said Pauline MacLaran, co-author of the upcoming book, "Royal Fever: The British Monarchy in Consumer Culture." ”It’s a fascination with a different kind of celebrity." 

This goes way beyond commemorative china.

The Center for Retail Research in Nottingham estimated that George provided a 243 million-pound ( 368 million) boost to the British economy in the nine weeks after his birth in 2013. But George was the royal couple’s first child, the heir to the throne. The immediate impact of a second child will be smaller, about 80 million pounds (USD 121 million), the center predicted. But the fact that it is a girl opens up a host of long-term opportunities.

This is a princess, after all, a real-life Snow White, Cinderella or Princess Anna from "Frozen." 

From the moment Saturday when she first appeared in public with a knitted cream bonnet and every day for the rest of her life, fashionistas will ask: Who is she wearing? A princess isn’t just a boon for this year. She’s a boon forever.

"It’s more fun in general terms and cultural terms when you are dressing up a girl," said Anusha Couttigane, a senior fashion consultant at Conlumino, a London-based retail research firm. "It’s just normal that girls attract more attention to fashion."