Princess Charlene of Monaco misses another royal milestone as she recovers from infection at secret location

Princess Charlene of Monaco continues to be absent from royal duties over nine months after she contracted an ear, nose, and throat infection during a conservation trip in South Africa.

Prince Albert II was joined by his and Charlene's children, seven-year-old twins Princess Gabriella and Prince Jacques, as he attended a boat-lighting ceremony to mark Sainte Devote Day on Thursday. Prince Jacques was seen giving a hand to his father as the monarch set alight a sailboat to mark the festival, reports Mail Online.

Albert's sister Princess Caroline of Hanover, his nephew Louis Ducruet, and cousin Melanie-Antoinette de Massy also attended the national celebrations. However, his wife Charlene, who used to accompany him on these events, was missing from the occasion.

It also came just a day after Charlene marked her 44th birthday alone as she recuperates from the illness at a location outside of Monaco that has not been disclosed. To mark her birthday, the former Olympic swimmer shared a slideshow of images from her personal album on her Instagram account.

The video included pictures from her childhood, the competitions she participated in, and her royal engagements. It also contained several pictures of her with her husband of a decade and their twin children. The clip was created by the Princess Charlene Foundation in South Africa, which promotes the benefits of sport; teaches basic swimming skills, water safety & drowning prevention.

The message accompanying the picture read, "Happy birthday, Princess Charlene! We honour you for how much you always give of yourself to change people's lives around the world, your passion and dedication to saving and changing lives is truly an inspiration."

"We trust this video of your journey thus far reminds you just how loved and appreciated you are," it added.

Princess Charlene also had to miss the celebration of her children's seventh birthday on December 10 last year, though it is believed the family got together on Christmas. It was reported last month that she is still months away from making a full recovery and rejoining her family at the Prince's Palace in Monte Carlo.