• Birthday in the Danish Royal Family
  • Princess Isabella turned 15 today
  • The royals shared a new birthday portrait

In the royal world, April 21 is a big day. For starters, it's the birthday of Queen Elizabeth II, who turned 96 years old this year.

But it's also a special day for the Danish Royal Family. Princess Isabella, daughter of Crown Prince Frederik and Crown Prince Mary, also turned 15.

Royal birthday portrait: Princess Isabella at 15

On Instagram, the Danish royals were sure to wish the young Princess a happy birthday. They shared a nice portrait of Princess Isabella and revealed how she'll spend her big day.

From Danish, the Royal House wrote: "Her Royal Highness Princess Isabella has a birthday and turns 15 today." As for how she'll spend her day, the royals say:

"The Princess is celebrating her birthday with family and friends, and to mark the occasion, the Crown Prince couple are delighted to share a new series of pictures of the birthday girl."

Also interesting:

The photoshoot shows Princess Isabella in formal wear and appearing very dignified. The 15-year-old royal is a granddaughter of Denmark's Queen Margrethe II, and she stands third in line to the throne.

Isabella's father Prince Frederik is the heir to the Danish throne, and her elder brother Prince Christian is next in line to be King.