Actually, only King Filip's parents, the retired King Albert and his spouse Queen Paola, attended the ceremony in the Saint Michael and Saint Goedele Cathedral in central Brussels, together with their son-in-law, Prince Lorenz. He is the husband of Princess Astrid, who left for an important trade mission to China.
15 November is Day of the Monarchy and this includes a holy mass to honour the Belgian king. During this mass, the Te Deum is being sung. While there are usually more members of the royal family attending, there were only three this time. Prince Laurent, Filip's younger brother, and his wife Claire had cancelled. After the Te Deum, there was another ceremony at the hemisphere in the Federal Chamber of Representatives.