Meghan Markle's simple outfit that sparked mass sales in 2019

Meghan Markle sparked mass sales this year with a simple wardrobe staple that's probably hanging in your wardrobe. Photo / Getty Images

The Duchess of Sussex has been crowned the most powerful dresser of 2019 after sparking mass sales and online searches with her simple-but-stylish outfit choices this year.

Meghan was a bigger fashion influencer than style icons Zendaya, Billie Eilish, Cardi B, Kylie Jenner, Timothee Chalamet and Harry Styles, according to the global fashion search engine Lyst.

After tracking more than 200 million searches online from 104 million shoppers, the platform found Meghan's outfits triggered an average 216 per cent increase in searches for similar styles across the year, reports News.com.au.

But one simple item in particular sent shoppers into overdrive.

Meghan paired the dress with a headscarf while visiting the Auwal Mosque. Photo / Getty Images

It was the humble shirt dress, which the Duchess was snapped wearing everywhere from cheering on friend Serena Williams at the US Open to official engagements on her royal tour of southern Africa.

"After she wore five different shirt dresses on the royal tour of South Africa, searches for the category grew 45 per cent over a month," Lyst's Year in Fashion report said.

Meghan paired this shirt dress with a pair of pointed heels. Photo / Getty Images

One of Meghan's most popular outfits, however, was the sheer Club Monaco dress she wore while visiting Archbishop Desmond Tutu in Cape Town.

The royal wore the black-and-white printed dress on the same day her five-month-old son Archie made his tour debut, and the images evoked strong memories of Princess Di cradling a young Prince Harry.

The tour was the family's first official visit to Africa as a family since their son Archie was born. Photo / Supplied

The Club Monaco dress sold out in less than 24 hours following a 570 per cent spike in searches, according to Lyst.

A J Crew skirt she wore also saw a 102 per cent increase in searches for the brand, it said.

Fellow powerful dresser Billie Eilish inspired hoardes of shoppers to buy neon green outfits this year, Lyst said, while Timothee Chalamet's sent credit cards tapping with his embellished Louis Vuitton bib at the Golden Globes.