On June 28, 2011, it was announced that Their Royal Highnesses Grand Duke Henri and Grand Duchess Maria Teresa of Luxembourg along with the Hereditary Grand Duke, Prince Guillaume of Luxembourg, will attend the Monaco princely wedding on July 2.

Per the Cour Grand-Ducale de Luxembourg:

Sur invitation de Son Altesse Sérénissime le Prince Albert II de Monaco, Leurs Altesses Royales le Grand-Duc, la Grande-Duchesse et le Grand-Duc héritier assisteront à la Célébration du mariage religieux de Son Altesse Sérénissime le Prince Albert II de Monaco avec Mademoiselle Charlène Wittstock.

Source and photos courtesy of: Cour Grand Ducale de Luxembourg