Monaco's royal twins hold up sweet sign for mum as Princess Charlene sits out National Day celebrations

Princess Charlene might have been forced to skip Monaco's National Day celebrations on November 19 but she wasn't far from the thoughts of her two children.

Twins Prince Jacques and Princess Gabriella, six, held up signs for their mum on the balcony of the Prince's Palace as they stood in front of dad, Prince Albert of Monaco.

"We miss you mummy," Princess Gabriella's read, while Prince Jacques held up a cardboard sign saying: "We love you mummy".

Prince Albert, 63, drew attention to the messages for his wife, as Princess Charlene recovers in an undisclosed location outside of the Principality.

Last week, the Prince's Palace issued a statement announcing the 43-year-old royal would be skipping the annual celebrations while in recovery.

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"Their Serene Highnesses have both decided that a period of calm and rest is necessary to ensure the very best recovery for Princess Charlene's health," the announcement on behalf of the couple said.

"Having battled with poor health over the past few months, the Princess is currently convalescing and will continue to do so for the coming weeks, allowing her time to recover from a state of profound general fatigue.

"In order to protect the comfort and privacy essential to her recovery, the Princess' location will remain strictly confidential."

Later, Prince Albert confirmed Princess Charlene's secret hideaway was out of the country.

"She is better, but she still needs rest and peace," Prince Albert told Monaco-Matin in an interview last Wednesday.

"She is not in the Principality, but we will be able to visit it very soon."

He added: "I cannot say more for discretion. There is fatigue, not just physical, that can only be treated with a period of rest and follow-up."

Princess Charlene returned home to Monaco two weeks ago, having spent eight months in her native South Africa after having two surgeries while there originally for charity work.

Despite the royal's absence, National Day celebrations went ahead on Friday with the rest of the extended Monaco Royal Family in attendance.

Sections of the family all posed together on the balcony for photos and waving at well-wishers.

Prince Albert's sisters Princess Stephanie and Princess Caroline also both helped with the young twins during the earlier ceremonies, including a military parade in the Palace courtyard.