Princess Charlotte has taken over from her mother the Duchess of Cambridge as the royal with the biggest fashion-influencing power, according to eBay.
Two-year-old Charlotte's knitted yellow cardigan, which she wore for her official birthday photo in May, was the most popular searched-for royal outfit in the last 12 months.
On the day, it sparked a 900% increase in the number of people searching for the royal toddler's clothes on the online auction site, followed by three searches an hour for the item across the whole month.
The John Lewis cardigan - which was adorned with pictures of sheep - sold out soon after Charlotte was pictured in it.
UK shoppers' favourite Kate outfit was the understated peach Alexander McQueen ensemble she wore to her sister Pippa's wedding, which generated a 200% increase in searches for Kate's clothes.
An eBay spokesman said: "Princess Charlotte has the biggest spend power of the royals this year. Her yellow cardigan worn in her birthday picture sparked the biggest percentage increase in searches for an item of clothing worn by any royal."
Netflix drama The Crown also resulted in a rise in the demand for all things regal, according to eBay's annual retail report.
Searches for "royal" more than doubled between November 1 and November 13 during which time Season 1, which charts the start of the Queen's reign, was released.
Murray Lambell, vice president of trading at eBay, said: "The Royal Family are hugely popular with British buyers with Her Majesty regularly attracting the attention of shoppers.
"But it's the youngest generation of royals who really generate the must-have fashion items - and are driving a new generation of shopping behaviour on eBay."
Kate is even more popular with American buyers than in the UK. Two people in the US search for "Kate Middleton" every hour, whereas in the UK, the Duchess inspires one search an hour.
Her most popular outfit with shoppers in the US was a semi-sheer, high collared, blue Mary Illusion Dot Dress by Indian designer Saloni, which she wore to a reception in April 2016.
It inspired six searches an hour for Kate's clothes the day after she was pictured in it.
Other trends included searches for Emma Stone's yellow La La Land dress, while retro brands received a boost from Netflix's eighties sci-fi drama Stranger Things, with searches for retro clothing up 400% in July when the series was released.
The most wanted fashion accessory on eBay this year with 37,383 searches was Primark's Chip purse - an item inspired by Disney's Beauty And The Beast.