1.5 million people like Princess Charlotte's birthday pictures

Prince William and Kate Middleton's Instagram posts hardly cross one million likes.

But when the royal couple shares pictures of their children, they elicit an overwhelming response on social media.

The Duke and Duchess of Cambridge recently celebrated the seventh birthday of their daughter Princess Charlotte.

Multiple picture of the princess taken by her mother were shared on Instagram ahead of Charlotte's birthday. The picture were liked by more than one million people.

Half a million others reacted when the couple shared some more pictures the next day.