Prince of Liège (French: Prince de Liège, Dutch: Prins van Luik, German: Prinz von Lüttich) is a substantive title awarded by King Leopold III of the Belgians to his younger son, Prince Albert (the future King Albert II), while he was second in line to the throne of Belgium on 7 June, 1934.
His wife, the former Queen Paola, was known as the Princess of Liège from their marriage in 1959 until their accession in 1993.
The title Count of Hainaut was traditionally reserved for the eldest son of the crown prince and King Leopold's brother held the title of Count of Flanders.
This meant that all the commonly used titles in the Belgian Royal Household had been given, so a new style had to be created.
The heir to the throne is awarded the title Duke or Duchess of Brabant.