Prince Guillaume of Luxembourg

Guillaume and Stéphanie have a son, named Prince Charles, born on 10 May 2020. He is second in the line of succession to the throne of Luxembourg.

Since 18 January 2016, the Hereditary Grand Duke has also been a member of the board of directors of Europäische Stiftung Kaiserdom zu Speyer Foundation.

At the occasion of his 30th birthday, he gave interviews during which stated that he was in a relationship with a "dear miss" that had been going strong for more than a year but insisted that they need some more time to evaluate their possible future. On 26 April 2012, the court announced the engagement of the Hereditary Grand Duke to the Belgian Countess Stéphanie de Lannoy. Guillaume and Stéphanie share a common descent from Charles Marie, Prince & 5th Duke d’Arenberg, which means that Guillaume's father and Stéphanie are 7th cousins; thus Guillaume is Stéphanie's 7th cousin once removed.

The civil wedding took place on Friday, 19 October 2012; the religious wedding took place on Saturday, 20 October 2012 at the Notre-Dame Cathedral.

Guillaume's education includes Lycée Robert-Schumann in Luxembourg; Collège Alpin International Beau Soleil and Institut Le Rosey boarding schools in Switzerland; and Royal Military Academy Sandhurst, Camberley, England. He began his higher education studies in the United Kingdom where he studied at University College, Durham and Brunel University, both in England. In 2006 he entered Institut Philanthropos in Fribourg, Switzerland, where he spent a year studying philosophy and anthropology. He later studied letters and political science at the Institut Albert-le-Grand in Angers, receiving his bachelor's degree with honors in 2009. His degree was issued by Université d'Angers, as a result of a partnership agreement between the two schools.

Guillaume has been heir apparent to the crown of Luxembourg since his father's accession in 2000. If he succeeds to the grand ducal throne, he will reign as Guillaume V (English: William V). He has been honorary chairman of the Board of Economic Development of Luxembourg since 2001.

In 1999, he participated in a charitable mission to Aguascalientes to provide the educational and social assistance to young people in one of the most deprived areas in Mexico. After having chaired for more than 10 years (2000–2011) in Kräizbierg Foundation, which works for people with disabilities; the Hereditary Grand Duke accepted the title of honorary president in March 2011.

During the summer of 1997, Guillaume participated as a member of Luxembourg Scout Movement in a humanitarian camp in Nepal. He involved in a reforestation project and other actions for the benefit of the less favored communities. In 2017, the Hereditary Grand Duke joined the board of directors of the World Scout Foundation to support the development of scouting around the world.

Guillaume, Hereditary Grand Duke of Luxembourg (given names: Guillaume Jean Joseph Marie; born 11 November 1981), has been heir apparent to the crown of Luxembourg since his father's accession in 2000.

Prince Guillaume was born in 11 November 1981 at the Grand Duchess Charlotte Maternity Hospital in Luxembourg City and is the eldest child of Grand Duke Henri of Luxembourg and his wife, Cuban-born Grand Duchess Maria Teresa. He was named after his father's youngest brother Prince Guillaume of Luxembourg. His godparents are Princess Marie Astrid of Luxembourg and Prince Guillaume of Luxembourg. Guillaume has four younger siblings: Prince Félix, Prince Louis, Princess Alexandra and Prince Sébastien.