Is Duchess Kate having a boy or girl? Color of her outfits may predict sex of baby No. 3

So is it a boy or a girl? Duchess Kate and Prince William have remained mum on the sex of their third child -- perhaps because they themselves may not know as royal tradition forbids them from finding out -- but it hasn't stopped the internet from coming up with their own theories!

Kate has stepped out in one stunning look after another while pregnant with baby No. 3, and one color, in particular, has had people speculating that baby No. 3 is indeed a boy. The 36-year-old royal has stepped out in a number of dazzling blue looks over the course of her pregnancy.

See all of Duchess Kate's blue maternity looks:

For the Royal Variety Performance, Kate sparkled in a glittering ice-blue Jenny Packham gown.

The mother of Prince Geoge and Princess Charlotte has also turned to beloved British brand Seraphine for a number of her maternity looks -- including this lace dress she's worn over and over again. And when she made her first official appearance alongside Meghan Markle, she also displayed her blossoming baby bump in another Seraphine look.

Another theory speculates that the royal family's Christmas card is also another hint that Kate is having a boy -- the whole family is decked out in powder blue-hued clothing in the photo taken before Kate was pregnant.

RELATED: Duchess Kate's pregnancy in photos:

But maybe Kate really just loves the color blue! For her official engagement photocall back in 2010, Kate looked beautiful in a blue Issa dress that quickly sold out. She's also worn the hue a handful of times throughout the years, stepping out in blue-colored looks by Alexander McQueen, Emilia Wickstead and many other famous designers.

Regardless of whether it's a boy or a girl, we can't wait to meet Kate and William's new bundle of joy!

Check out the complete timeline of Duchess Kate's pregnancy here to get caught up on all things baby No. 3.