Princess Sofia, Princess Estelle, more royals celebrate Sweden's National Day

The Swedish royal family was out in full force on Thursday to mark their country’s National Day. Since 1983, Sweden has celebrated its National Day on June 6. The date coincides with two important events in the country’s history — King Gustav Vasa's coronation in 1523 and the adoption of a new constitution in 1809. In celebration of the holiday, the royal family opens the doors of the palace to the public and local musicians and artists perform throughout the day at various events. As in previous years, the Swedish Royal court also released new portraits of future Queen, Princess Estelle, and her younger brother Prince Oscar. Click for photos of the royal family celebrating Sweden's 2019 National Day…

This year, Prince Carl Philip and Princess Sofia had the honor of opening the royal palace's gates in Stockholm. Writing on their personal social media account, the couple, who are parents to Prince Alexander and Prince Gabriel, penned, "Happy national day from us! 🇸🇪."

In honor of Sweden's National Day, the royal court shared three new images of Crown Princess Victoria and Prince Daniel's children, Princess Estelle and Prince Oscar. The sweet sibling duo posed for photos at their home in the gardens of Haga Palace.

For the annual photo, the seven-year-old Princess wore her traditional blue, yellow, and white folk dress, while sweeping her golden locks up into a ponytail. Meanwhile, Estelle's little brother, three, sported a blue button-down shirt and dark shorts for the photo session.

Doting big sister Estelle held her younger brother's hand as they strolled through the garden in photos shared by the royal palace as a 2019 National Day greeting.

Sweden's Queen Silvia, channeling a Jackie O look, greeted children during National Day celebrations at Gammelgarden in Ludvika, which this year celebrates 100 years as a city.

Royal dad-of-two, Prince Carl Philip was dressed to the nines in uniform as he participated in a ceremony at the Royal Palace in Stockholm.

Her Majesty and King Carl XVI Gustaf had prime seats at the town square in Borlange, Sweden, to take in the day’s festivities.

Princess Madeleine marked the holiday with a special book signing. The royal, who was joined by her mother Queen Silvia, penned on her personal social media channel, "So honored to be signing my book “Stella and the Secret” today on National Sweden day! The palace was open to everyone and it was so exciting to see so many people, so proud to be Swedish 🇸🇪!!"

Prince Daniel shared a tender moment with his firstborn, Estelle, in Skansen during a ceremony with the Swedish royal family.

Two future Queens. Crown Princess Victoria walked hand-in-hand with her little girl as the royal family gathered together on Sweden's National Day.

A royal family affair. Princess Madeleine, Princess Sofia, Prince Carl Philip, King Carl XVI Gustaf, Queen Silvia, Crown Princess Victoria, Princess Estelle and Prince Daniel sat together for a ceremony celebrating Sweden's National Day in Skansen. Madeleine's husband Christopher O’Neill was noticeably absent from the festivities.