Meghan Markle and Kate Middleton [Courtesy]

Meghan Markle has beaten her sister-in-law Kate Middleton to be crowned the 'most iconic' member of the royal family.

The Duchess of Sussex has won the title after PrettyLittleThing, analysed how much interest there is in the fashion of the royals. The global fashion brand reviewed internet search volumes in the UK and US.

Over the last year, there has been an increase in demand to know about the outfits worn by royals such as Sophie, Countess of Wessex, Princess Anne and Camilla, Duchess of Cornwall, Daily Express reports.

The team carrying out the study said the number of searches for Meghan has doubled in the last year while Kate's looks increased by 84% during the same time frame.

But Sophie Wessex, Princess Anne, and Camilla's outfits had a bigger increase in search than both Meghan and Kate, which the report discussed.

It said: "It is likely that this is due to both Meghan and Kate consistently setting trends and being huge style icons in their own right."

The data shows Meghan also came out top on as the most "iconic" royal for style with her looks searched thousands of times.

Meghan stunned in a pastel outfit. [Courtesy]

It found Meghan's outfits had been looked up a whopping 148,550 times while Kate clocked up 145,400 searches. Any outfits worn by Kate and Meghan will often sell out quickly as fans want to copy their style.

Commenting on Kate's looks, a fashion expert explained why they may be desired so much.

Editor of British Style Society Natasha Henson said Kate wears items that are accessible to many which could explain her popularity. She said: "Kate often opts for comfortable yet stylish casual attire to fit her role as a young royal and a hands-on mother.

"These elements may indicate that although she is a prominent public figure, she still likes to feel relaxed yet fashionable whether she’s attending an event or enjoying a family day out."

Mum-of-three Kate, 39, is also happy to wear her favourite looks on multiple occasions.

Natasha added: "Kate appears to have understated confidence in her style choices and chooses pieces that represent her position as a positive role model.

"She also isn’t afraid to re-wear statement pieces."

Meghan wowed in a head to toe lack outfit. [Courtesy]