Have you ever noticed this adorable detail about Princess Charlotte?

From the editors of LOOK

In case you missed it, Kate Middleton and Prince William released their annual Christmas card this week.

The sweet photo – which was taken before they announced that the Duchess of Cambridge is expecting their third child – is one of their last official photographs as a family of four.

It was captured by royal photographer Chris Jackson, who also snapped the lovely picture of Prince George and Prince William together on George’s first day of school in September.

Of course, both George and his little sister Princess Charlotte look absolutely adorable in the image.

George, four, shows his naughty side with one sock rolled down, while two-year-old Charlotte is the image of her mum in a blue dress and matching shoes.

But there is one interesting thing that royal fans have noticed about Charlotte. The toddler is wearing a blue bow in her hair, which has actually become a bit of a trademark.

She sported a red bow when the family visited Warsaw back in July, a pink one in Hamburg that same month and a blue version in Berlin a few days later.

In fact, she’s pretty much worn one for every public appearance she’s made since growing hair.

We’re not sure whether Kate, 35, is helping her daughter make a fashion statement or if she’s just trying to keep her locks out of her eyes – but whatever the case, it’s super-cute.

We can’t wait to meet the third mini Kate and Wills!