Photo: Royals on their way to King's Day in Groningen

King Willem-Alexander, Queen Maxima, and princesses Amalia, Alexia and Ariane are on their way to celebrate King's Day in Groningen.

"On our way to a sunny King's Day in Groningen. We are looking forward to it", the King said with a photo released on Twitter.

King Willem-Alexander turns 51 years old today.