Prince Nikolai, 23, the nephew of Crown Prince Frederik and Crown Princess Mary, will no longer be able to use the title His Royal Highness after he and his three siblings were told by their grandmother, the Queen, that the move will be "good for them in the future".
Nikolai's mother Countess Alexandra's press secretary' has since questioned why the change couldn't have waited until the siblings' wedding days, as they would "lose their titles anyway".
"My whole family and I are of course very sad. We are, as my parents have also stated, in shock at this decision and at how quickly it has actually gone," Prince Nikolai told Danish newspaper Ekstra Bladet.
"I am very confused as to why it has to happen like this," he added.
Countess Alexandra, who is also mother to Prince Felix, 20, shared that she is "very sad" and "shocked" by the decision, with Helle von Wildenrath Løvgreen, press secretary to Countess Alexandra, telling CNN, "She can't believe why and why now, because there's no good reason."
"They would lose their titles anyway when they get married one day. Her sons are young men so maybe they might get married in the near future so why shouldn't it wait until that day so that the titles would disappear on a happy day?"
Prince Joachim, the youngest son of Margrethe, claimed his children Nikolai, Felix, Henrik, 13, and Athena, 10, were only given five days' notice of the change.
The palace then hit back, saying in a statement that there were "lots of emotions" but the decision was a "long time coming" and was designed to "future-proof" the monarchy.
Joachim said his children had been "harmed" by the news they'd no longer be able to use His or Her Royal Highness and had been stripped of their prince and princess titles.
"We are all very sad. It's never fun to see your children being harmed. They are been put in a situation they do not understand," he told Ekstra Bladet.
Alexandra, who was married to Prince Joachim for 10 years until 2005, told Danish magazine Se og Hør, "This comes like a bolt from the blue. The children feel ostracized. They cannot understand why their identity is being taken away from them."
Her spokesperson also claimed Joachim found out the news from an aide and not the Queen herself.
The change does not affect Frederik and Mary's children Prince Christian, 16, Princess Isabella, 15, and 11-year-old twins Prince Vincent and Princess Josephine.
It comes after the family recently put on a united front for Queen Margrethe's Golden Jubilee.
Queen Margrethe's reasoning was reportedly to allow her grandchildren to "shape their own lives without being limited by the special considerations and duties" that comes with being part of the Danish royal family.
At an event in Copenhagen, she defended the decision saying, "It is a consideration I have had for quite a long time and I think it will be good for them in their future. That is the reason."
With the new changes, Nikolai, Felix, Henrik and Athena will be known as either His Excellency Count of Monpezat or Her Excellency Countess of Monpezat from January 1, 2023.
All four siblings will maintain their place in the order of succession.
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