(L-R) Luxembourg's Prince Louis, Princess Stephanie, Crown Prince Guillaume, Princess Alexandra, Grand Duchess Maria Teresa, Grand Duke Henri, Prince Felix, and his wife Princess Claire, and Prince Sébastien pose in jeans at Berg Castle. All family members went for the relaxed approach with the men of the party wearing shirts with open collars, while Princess Stephanie donned a pink jumper and Princess Claire and Princess Alexandra opted for floaty white tops. Princess Claire of Luxembourg and Prince Felix on National Day in June 2018. Prince Louis, Princess Claire and Prince Felix, Princess Alexandra, Prince Sebastien (L-R, back row) and Luxembourg city's mayor Lydie Polfer, Prime Minister Xavier Bettel, Grand Duchess Maria Teresa, Grand Duke Henri, Mars DI Bartolomeo, Prince Guillaume of and Princess Stephanie (front row) on Luxembourg's National Day in June 2018 Princess Tessy of Luxembourg at an awards ceremony in Utah in January 2017, a month before divorcing Prince Louis Prince Guillaume and his wife Princess Stephanie of Luxembourg move to London this month where he will undertake post-graduate training at the Royal College of Defence Studies, while Princess Stephanie studies art history at the Sotheby's Institute.