Library picture: Prince Sébastien is seen (on right) with his parents, Grand Duke Henri and Grand Duchess Maria Teresa, during his graduation ceremony at Royal Military Academy Sandhurst in August 2017 Cour grand-ducale/Lola Velasco

Library picture: Prince Sébastien is seen (on right) with his parents, Grand Duke Henri and Grand Duchess Maria Teresa, during his graduation ceremony at Royal Military Academy Sandhurst in August 2017 Cour grand-ducale/Lola Velasco

Grand Duke Henri celebrates his sixty-third birthday on Monday while Prince Sébastien blows out 26 candles on the cake.

The latter was touted as one of Europe’s last eligible royal bachelors after Prince Harry announced his engagement to Meghan Markle last year.