Kate Middleton, Prince William hit 13 million followers on Instagram as Prince George turns 8

Kate Middleton and Prince William's official Instagram account "Duke and Duchess of Cambridge " has crossed 13 million followers.

The royal couple hit 13 million mark as they celebrated the eight birthday of their son Prince George.

The Duke and Duchess follow only 113 people on the Facebook-owned social media app.

They have amassed 13 million followers by sharing only 2338 posts on the photo and video sharing application.