On the 19th and 20th of October 2012, Guillaume, Hereditary Grand Duke of Luxembourg, and Countess Stéphanie de Lannoy married in both a civil and religious ceremony which reportedly cost 500,000 euros - or $650,000 US. 

Their civil ceremony was held on the 19th (with Stephanie also becoming a naturalized Luxembourg citizen on the same day). It was a small service conducted by Luxembourg Mayor Xavier Bettel which took place in the Town Hall (a break from tradition as the civil ceremony is usually held in the Grand Ducal Palace). Afterwards, the couple greeted the assembled crowds and collected gifts like paintings from children in the crowd. The couple spent over an hour speaking to those in the crowds. 

Stephanie wore a white suit with minor silver embellishments on the pockets, arms and down the center by Chanel. She wore matching silver heels by the designer. Continuing the Chanel theme, her silver bag was also by the designer.

That evening a gala dinner was held at the Grand Ducal Palace for the guests invited to the ceremony the next day. The guests included an array of foreign royals. Stephanie wore a gorgeous couture long sleeved lace Elie Saab gown with the Vine Leaves Tiara. 

Guests dined on wild sea bass and lobster, chicken, green cabbage, and dark chocolate pears. 

The Roman Catholic religious service took place in French the next day on October 20th at the Notre-Dame Cathedral in Luxembourg at 11:00 am. It was officiated by Archbishop Jean-Claude Hollerich of the Roman Catholic Archdiocese of Luxembourg. Stephanie walked down the aisle with her eldest brother - Count Jehan - due to their father being confined to a wheelchair. However, when she arrived at the altar, her father was helped to his feet so he could kiss his daughter and speak to her and her groom for a few moments. 

The wedding attendants included Guillaume's sister, Princess Alexandra and Stephanie's niece, Antonia Hamilton as the maids of honor. The flower girls and ring bearers were Stephanie's nieces and nephew - Madeleine Hamilton, Countess Caroline de Lannoy, Countess Louise de Lannoy, Isaure de le Court, and Lancelot de la Court - and Guillaume's nephew - Prince Gabriel.

The bride and groom exchanged rings made of fair trade gold. After exchanging vows and receiving a blessing from the Archbishop, the Luxembourg national anthem was sung and the couple signed their marriage register. 

Stephanie wore a custom Elie Saab lace wedding gown featuring three quarter sleeves, high neckline that dipped in the back, and a 4.5 meter train. According to The Royal Splendor, "Masses of fabric went into this creation: 70 meters of silk crepe and tulle for the lining, plus another 30 meters of satin organza, 50 meters of Chantilly lace, and 40 meters of Calais lace. More silk tulle was used for the veil. The leafy pattern embellished all over the ensemble included 50,000 pearls, 80,000 crystals, and 10,000 meters of silver embroidery thread."

She chose to wear her family tiara (the Lannoy) for the occasion as her sisters and sisters-in-laws had done before her. Stephanie also wore diamond earrings, as well.

The wedding was a joyous occasion, but marked with sadness for the future Grand Duchess. Tragically, Stephanie's mother died after suffering a stroke just two months before the wedding. Stephanie wore her mother's ring during the ceremonies to keep her close to her heart. An additional tribute to her mother saw the statue of the Lady of Consolation in the cathedral being draped in her mother's veil.

Aside from the Grand Ducal Family, royal guests included the majority of the Belgian Royal Family; Queen Margrethe, Prince Henrik, Crown Prince Frederik and Crown Princess Mary of Denmark; King Constantine, Queen Anne-Marie, Crown Prince Pavlos and Crown Princess Marie-Chantal of Greece; Princess Caroline of Monaco; then-Queen Beatrix, Prince Willem-Alexander and Princess Maxima of the Netherlands; King Harald, Queen Sonja, Crown Prince Haakon, Crown Princess Mette-Marit, and Princess Martha Louise of Norway; then-Prince Felipe and Princess Letizia of Spain; Queen Silvia, Crown Princess Victoria, Prince Daniel, and Prince Carl Philip of Sweden; and the Earl and Countess of Wessex.

A reception was held after the wedding at the Grand Ducal Palace where the couple waved to the crowds from the balcony and shared a kiss.