"The princess celebrates her birthday with family and friends, and on the occasion of the day, the Crown Prince and Crown Princess have the great pleasure of sharing a new photo series of the birthday girl."
The timeless photos taken by photographer Hasse Nielsen captured Isabella posing in a sharp suit, while a black and white close-up showed a profile shot of the young royal.
While Isabella has inherited her mother's facial structure and button nose, some royal watchers also pointed out the striking resemblance she shares with her father Frederik, Crown Prince of Denmark.
"So stunning 🙏🙏 beautiful looks from her mother and father. Happy Birthday Princess Isabella 🎉🎉," one royal fan wrote.
The princess has taken after her father, sharing the same ocean blue eyes and cheekbones.
Born on April 21, 2007, at the Rigshospitalet or Copenhagen University Hospital, Princess Isabella was Mary and Frederik's second child.
When Isabella was born, she became the first Danish princess born in Denmark for over 60 years. The last before her was Queen Anne-Marie, Queen Margrethe's youngest sister who was born in 1946.
It wasn't until 2015 that she undertook her first official royal engagement, then aged eight, when she christened a ferry named in her honour in Denmark.
Mary seems to have an incredibly close relationship with her eldest daughter too, even letting Isabella borrow from her wardrobe.
On several occasions the 15-year-old has been spotted wearing her mum's clothes or jewellery.
She already looks like Mary's mini-me, but it's even more obvious when she styles herself like her mum too.
While Isabella is currently third in line to the Danish throne after her father and elder brother, it's unlikely she'll ever be Queen of Denmark.
When Prince Christian has children, they will take precedence over Isabella in the line of succession.
That means she'll only be queen if Frederik, Christian and his future children are all unable to fill the role of Danish monarch.