Prince Albert and Princess Charlene's twins planned birthday surprise for Monaco royal

Prince Albert celebrated his 65th birthday on Tuesday, complete with a very special surprise from his young children.

The Monaco royal, who had an Olympic career before his reign, shares eight-year-old twins, Princess Gabriella and Prince Jacques with his wife of nearly 12 years, Princess Charlene.

WATCH: Prince Albert's life - Olympic career, marriage and more

The Prince's Palace's official Facebook page shared photographs from Albert's birthday, which showed him on the balcony with Jacques and Gabriella as the Prince's Band of Carabiniers performed a special musical number.

In a statement, the palace shared that Albert had enjoyed a family lunch with Charlene and their children, before Jacques and Gabriella invited their parents to a special theatrical performance "The Witch of the Broom Closet," created especially for the occasion.

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Pictures show the family-of-four outside the Théâtre des Muses in Monaco, with Albert sporting a suit with a colourful tie, and Charlene looking elegant in a black jacket over a rollneck jumper and cropped tan trousers with heels.

Princess Gabriella was dressed in a furry blue jacket and matching tights for her father's birthday surprise, while Jacques matched his twin sister in a blue bomber jacket.

Princess Charlene with twins in 2015
Princess Charlene with twins in 2015

The couple became parents in 2014

Ahead of the celebrations, Albert revealed to PEOPLE magazine that his children told him they had planned to "kidnap" him.

Speaking about his plans, the Monaco head-of-state said: "It's going to be very subdued. We'll have a little family lunch on Tuesday. Afterwards, when the children return from school, I'm going to be kidnapped."

He added: "Really. I've been told to be available to be kidnapped. At 5:30. It's a secret. The kids want to kidnap me. They want to take me to a play at a theatre, but actually, I've only been warned I'm going to be kidnapped."

Albert and Charlene welcomed their twin children in December 2014. The Prince is also the father of Jazmin Grace Grimaldi, born in 1992, with real estate agent Tamara Rotolo.

He then confirmed he was the biological father of Alexandre Grimaldi-Coste, born in 2003, whose mother is Nicole Coste, a former Air France flight attendant from Togo, in May 2005, just before he was enthroned as Prince of Monaco.

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