The issued press released read as the following:
Their Royal Highnesses the Grand Duke and the Grand Duchess have the great joy of announcing that Prince Félix and Princess Claire are expecting their first child. The birth is expected to take place in the month of June. The Grand Duke, the Grand Duchess, Grand Duke Jean and the entire Grand Ducal Family as well as the Lademacher family are delighted about this news.The baby will be the third grandchild for Grand Duke Henri and Grand Duchess Maria Teresa as well as the sixth great-grandchild of Grand Duke Jean. Just like the children of any other younger son of a Grand Duke or Grand Duchess born within an approved marriage, the child will bear the title of a Prince or Princess of Nassau and Prince or Princess de Bourbon de Parme and be styled as a royal highness.
Congratulations to the parents-to-be!
Source: Cour grand-ducale