United Kingdom, March 9 -- Prince Frederik of Luxembourg has died at the age of 22.

The royal - who was the son of Prince Robert of Luxembourg and Princess Julie of Nassau - passed away on March 1 following a long battle with a POLG Mitochondrial, his father announced on Saturday (098.03.25) evening.

In a message posted onto the PLG Foundation website, he said: "It is with a very heavy heart that my wife and I would like to inform you of the passing of our son, The POLG Foundation Founder and Creative Director, Frederik.

"Last Friday, February 28th, on "Rare Disease Day", our beloved son called us in to his room to speak to him for one last time. Frederik found the strength and the courage to say goodbye to each of us in turn - his bro...