Currently all the Danish Counts and Countesses of Monpezat are also princes and princesses of Denmark.
In future generations that may chance. I don't expect any of the Queen's grandchildren to loose their current titles by marriage.
Time will tell. My point was:- regardless of whether or not Princes Nikolai and Felix lose their princely titles upon marriage, they would in all likelihood be invited to official galas. They are in the line of succession and are close to their uncle, CP Frederik, and their cousin, Prince Christian. Hence, the princes/counts could still have a use for the Queen Alexandrine tiara.
1351