You probably missed Kate Middleton's subtle tribute to Diana in Royal Christmas card

It's so heartwarming

It's become a bit of a tradition for the women close to Prince William and Prince Harry to pay tribute to their late mother Princess Diana: Kate Middleton included this secret nod on her wedding day, and Meghan Markle's engagement outfit was another nod to Diana.

And the Duke and Duchess of Cambridge's Royal Christmas card this year was no exception, though the nod was so subtle you might have missed it.

You see for the posed portrait, Kate chose to wear a pale blue skirt suit by Catherine Walker. As you may know, Catherine Walker was one of Diana's favourite designers, and she was credited for many of her perfectly tailored outfits.

But the echo doesn't stop there, as Princess Diana also loved wearing blue skirt suits, and though she wore some by different designers such as Versace, she did wear a very similar design to Kate's back in 1988, and another one in 1997, both designed by Walker.

Kate has worn the suit before, in 2016 for an official engagement, but it's lovely that she chose it again for the portrait, especially at a time when loves ones are in our mind.

In the picture, shot by Chris Jackson, Prince William, Prince George and Princess Charlotte are also wearing various shades of blue.

Not that we're overanalysing or anything.