"It put us on the map," boutique co-owner Amaia Arrieta tells PEOPLE of the socks
Credit: Courtesy Duchess of Cambridge

Of the many reasons we adore Prince George, perhaps No. 1 on the list is the fact that he reminded the world exactly how charming knee socks can be.

Of course, his mom Princess Kate is responsible for the picture-perfect look – and now PEOPLE is taking you inside the children’s boutique where Kate buys those famous socks in the new episode of our ongoing video series, Make Me Kate.

Tucked away in London’s quaint Chelsea Green area is a wonderland of knee socks and timeless children’s clothes: Amaia, a tiny, independent boutique co-owned by Spanish-born Amaia Arrieta and French-born Segolene Tresca.

Not only does Kate love the brand’s traditional ribbed socks for 2-year-old George – she has them in at least five colors and buys them again and again when he outgrows them – but she has also picked up tights at the store for George’s little sister, Princess Charlotte.

“It’s put us on the map,” Arrieta tells PEOPLE. “We are a very small shop in Chelsea, but now many people around the world know us.”

Still, Arrieta admits that even she was surprised by the vast popularity of the knee socks, which are housed in a variety of colors in a glass case at the center of the store – and can now be purchased for $10 at PEOPLE Shop.

“I think it has been a kind of a revolution!” she says with a laugh. “They were a good seller before, but now it’s just crazy. In Spain and [throughout Europe] it’s always been a classic, but not really for everyone.”

Want to keep up with the latest royals coverage? Click here to subscribe to the Royals Newsletter.

With Charlotte’s first birthday just weeks away on May 2, what might we expect to see George’s little sister wearing on her special day?

“Pink!” says Arrieta. Kate “has gone all pink for Charlotte, which is very traditional for girls. Baby pink, powder pink, dusty pink – it’s all very pink.”

To buy the same knee socks worn by George, visit PEOPLE Shop. Customers can get an additional 20% off with code ROYAL20 at checkout.