Fans of the British royal family are celebrating the birth of the Duke and Duchess of Cambridge's second child, a daughter named Charlotte Elizabeth Diana, born on Saturday. But as Kate Middleton, the wife of Prince William, showed off her new arrival to the world, the focus wasn't just on the newborn - but also on what the duchess was wearing.
Much like in July 2013, following the birth of Prince George, Middleton chose to wear a custom-made outfit by British fashion designer, Jenny Packham. This time around, the dress was white with a yellow floral pattern.
Packham is just one of a string of British designers endorsed by the duchess, who also likes to wear more affordable high street names like Cath Kidston.
Here, CNBC takes a look at which brands have won extra attention and sales because of "the Kate Middleton effect."
- By CNBC's Alexandra Gibbs
The royal has long supported British brand ASOS, and wore a $42 blue dress from the online retailer during her first pregnancy back in 2013.
This March, Middleton wore a maternity polka dot dress by ASOS to visit Brookhill Children's Centre in South East London. A flurry of pregnant women rushed to purchase the £35 ($53) dress afterwards, which sold out online within minutes.
It's not just Middleton's own fashion sense that drives fans to the shops, but also the products she buys for those around her.
In December 2014, fashion and home furnishings brand, Cath Kidston, was forced to restock a £28 tank top ($42), featuring a royal guards design, after Prince George wore it for the 2014 Royal Christmas photographs.
Founded in 2002, natural skincare company, Trilogy, got a royal boost earlier this year.
In March, Us Weekly magazine reported that a source close to Kate Middleton said the duchess loved Trilogy's rosehip oil, and was using it during her pregnancy.
The product - which costs around £16.50 ($25) for a 20ml bottle - sold out shortly after the article was published. Trilogy claims the organic oil provides "all-over nourishment and repair for optimum skin health" and helps with stretch marks and ageing skin.
Catherine Walker first came to the limelight in the 1980s as a favorite of the late Princess Diana. Prince William's mother sported more than 1,000 dresses by the British designer.
Now the brand has returned to the public eye, with both Middleton and her mother regularly spotted wearing the label. Middleton has worn the brand on international tours - such as on her 2014 trip to New Zealand - as well as during her latest pregnancy.
At one of her final public outings before the birth of her daughter, Middleton wore a Catherine Walker brown coat for a St. Patrick's Day parade in March.
British ceramics manufacturer, Emma Bridgewater, likes to celebrate the royal family in her designs, launching a collection for the royal wedding back in April 2011, and another in 2012 to celebrate the Queen's Diamond Jubilee.
She also made a "Hooray for George" mug in 2013 to celebrate the birth of the Duke and Duchess of Cambridge's first child.
Similarly, Bridgewater is expected to launch a commemorative mug for the new arrival, according to a Press Association report. It comes after Middleton visited Bridgewater's factory in February this year.
From blazers to dresses, the duchess is often spotted in Spanish high street brand, Zara. Earlier this year, she went shopping at Zara eight months into her pregnancy to pick out shoes for George, according to media reports.
Back in December 2013, Middleton made headlines when she wore a £19.99 faux-crystal necklace by Zara to a film premier in London, with a designer cream gown by Roland Mouret.
Middleton isn't the only trendsetter in the royal family, with her clothing choices for Prince George also selling out fast.
During the royal tour to Australia, George wore three items by British luxury childrenswear brand, Rachel Riley - and all sold out almost immediately.
The nautical-themed navy dungarees that George wore, which cost £75 ($113), sold out in two sizes and had an eight-week waiting list, according to media reports.
Another British brand that has skyrocketed on Middleton's endorsement is Hobbs. In fact, the label has become so popular internationally that it has branched out to the U.S., launching in Bloomingdale's stores in 2014.
Sales in the U.S. took off "like a rocket," Clare Dobbie, Hobbs marketing and e-commerce director, told Women's Wear Daily last year.
Back in London, a brown Hobbs silk dress sold out this January after photographs of Middleton wearing the outfit emerged. The dress cost £50 ($75) in the sale, marked down from £169.
Maternity brand Seraphine has a number of celebrity endorsers, including Hollywood actresses Halle Berry and Angelina Jolie — along with Middleton.
After the duchess wore a Seraphine dress for her first official family portrait with Prince George and Prince William, the £46 ($70) fuchsia frock reportedly sold out within two hours.
The dress sold in every color and there was a four-week waiting list, according to "Hello!" magazine.