Kate Middleton shares a rare selfie video on Instagram

Kate Middleton recorded a video message for millions of royal fans.

The Duchess of Cambridge shared the rare selfie video to mark the Children's Mental Health Week.

Here is what she wrote alongside her Instagram post:

"Tomorrow is the start of Children's Mental Health Week - an opportunity to remind ourselves not just how important our own children's mental health is but also parental wellbeing too.

We look forward to sharing more about this year's theme of expressing yourself throughout the week."