Prince Joachim, 53, is sixth in line to the throne after his brother and his brother's children.
He was previously married to Alexandra, Countess of Frederiksborg, in 1995, before their divorce in 2005. They share two children: Count Nikolai and Count Felix. He then married French-born Marie Cavallier in 2008. They share Count Henrik and Countess Athena.
Queen Margrethe announced in September 2022 that she would be taking away his four children's prince and princess titles and they would instead receive the titles of counts and countesses.
His mother's decision apparently came as a surprise to Joachim, who claimed he was only given notice of the change five days before it was made public.
"My kids don't know which leg to stand on. What they should believe," he said in a 2022 press statement, according to Town & Country. "Why should their identity be removed? Why must they be punished in that way?"
For her part, the queen has said it was something she had been considering for a while.
In October 2022, Joachim met with his mother to discuss the issue, Danish newspaper BT reported, according to People magazine.
"It is correct that the Queen and Prince Joachim have spoken together at Fredensborg," a spokesperson for the royal household told BT. "Everyone agrees to look forward, and as the Queen herself has expressed, she and Prince Joachim want calm to find their way through this situation."
Joachim lives in Paris with his family and, later this year, they will be taking a page out of Prince Harry's book by moving stateside.
In March 2023, the Danish royal palace wrote on Instagram, "On 1 September 2023, His Royal Highness Prince Joachim will take up a new position under the Ministry of Defense as defense industry attaché at the Danish Embassy in Washington D.C., where the Prince, as Denmark's representative, will in the coming years help to strengthen the defense industry cooperation with the USA and Canada."
The Danish royal household did not respond to Insider's request for comment.