Meghan, 36, caused controversy for wearing a pair of ripped jeans and a white shirt during Prince Harry's trip to Canada, while Kate has always stuck to conservative looks, hardly ever causing debates with her classic ensembles.
So, how do their styles differ? Firstly, Prince Harry is sixth in line for the throne, while Prince William is second behind Prince Charles, meaning their royal responsibility is completely different.
Speaking about how Kate's importance in the royal family reflects her style, stylist Lorna Weightman told The Independent: "Typically I think she dresses a bit older than she actually is, I’m sure that’s a lot to do with the circumstances she’s in, which requires her to dress conservatively. She’s sizing herself up for that safe, princess role."
While Megan prefers a much more laid back look, revealing her top fashion tip is to mess things up a bit, which is the total opposite to Kate's polished look.
Speaking to Glamour UK magazine, Meghan said: "If your outfit is on point, one thing has to be off for you to look perfect."
While a source told the MailOnline: "People love her style because it is relaxed, elegant and chic but also quite funky, much more streetwise than the Duchess of Cambridge."
The other clear difference between the two is the fact Kate made the move to much more expensive designer labels in recent years, ditching her favourite high street numbers from Topshop and Zara, while Meghan loves brands that don't make her "feel guilty".
So it's no surprise the outfit she wore during her first public appearance with Prince Harry sold out shortly after she stepped out in it.
Could the 'Meg Effect' take over the 'Kate Effect' as the American actress becomes more popular?
Even the stylists believe Meghan could have a huge impact on British brands.
With a source telling the MailOnline: "Her appearance on the scene is good news for the British fashion industry, if she chooses to champion it."
Which look do you prefer? Let us know in the poll above!
Credits:- Fashion, Fashion, Fashion