It will be the biggest gathering of European royals since the baptism of Sweden's Princess Estelle.
The provisional guest-list for Luxembourg's royal wedding has been released – and representatives from key royal households are preparing to don their finery for the spectacular two-day celebrations on October 19 and 20.
Estelle's parents Crown Princess Victoria and her husband Daniel will watch as Prince Guillaume, Hereditary Grand Duke, weds Countess Stephanie de Lannoy.
Norway's future king and queen, Haakon and his wife Mette-Marit, will also bear witness as Europe's last single royal heir becomes a married man. His father King Harald and mother Sonia will accompany them.
No royal celebration would be complete without the Netherlands' vivacious Princess Maxima. She will attend with her husband Willem-Alexander and mother-in-law, Queen Beatrix.
Prince Naruhito of Japan will make the long journey to Luxembourg for the wedding.
The guest list is provisional and so far there has been no news on whether Danish royals Crown Prince Frederik and his glamorous wife Mary will complete the regal line up.
More names will be added as Stephanie and Guillaume's big day draws closer, and the Danish couple are bound to figure.
As details of the guest list are released, it has been revealed that bride-to-be Stephanie will be granted citizenship of the world's second richest country.
Royal Guest List
Members of the Luxembourg Royal Family
Grand Duke Henri and Grand Duchess Maria Teresa of Luxembourg
Prince Louis and Princess Tessy
Members of the Lannoy family
Count Philippe, Father of the Bride
Count and Countess Jehan and Beatrice
Count and Countess Christian and Luisa
Count and Countess Olivier and Alice
Countess Isabelle and Jean Charles de le Court
Members of other Royal Families
King Harald and Queen Sonia of Norway
Crown Prince Haakon and Princess Mette Marit of Norway
Princess Marta Luisa and Ari Behn
Crown Princess Victoria and Prince Daniel of Sweden
Queen Beatrix of Holland
Crown Prince Willem Alexander and Princess Maxima of Holland
Crown Prince Naruhito of Japan