Princess Charlene exercised a very rare royal privilege on Monday – which applies to fewer than ten royal women.
The Monegasque royal, 48, invoked her "privilège du blanc" to meet Pope Leo XIV in northern France, alongside her husband, Prince Albert, 62.
Charlene looked impeccably glamorous in head-to-toe Christian Dior as she arrived at the Robert Schuman Conference Centre in Metz for a conference called "At the Roots of Europe: For Peace and Unity".
She wore a tailored white trouser suit with gold buttons and white embroidery around the collar, adding pearl earrings as her only jewellery and a matching quilted bag.
© POOL/AFP via Getty ImagesPope Leo delivered an address at the conference, which came at the end of his four-day visit to France.
The royal couple was also joined by President Emmanuel Macron of France and his wife Brigitte, who were wearing black, and Grand Duke Guillaume of Luxembourg.
Why was Charlene wearing white when the others did not?
The "privilège du blanc" (the privilege of the white) exception permits only queens and princesses from Catholic countries to wear white in front of the Pope, and Charlene is included.
It meant that Brigitte, 73, wore black, adding a gold brooch to accessorise.
Charlene first invoked the protocol during an audience with Pope Benedict XVI in 2013.
© POOL/AFP via Getty Images"It is a historical concession from the Holy See to the Catholic sovereigns of certain monarchies," protocol expert Gloria Campos García de Quevedo, professor at Camilo José Cela University, told HELLO!'s sister publication ¡HOLA!.
"The attire must convey respect, sobriety, and a sense of institutional decorum."
On Monday, Charlene followed in the footsteps of Queen Sofia of Spain, King Felipe's mother, who became the first to wear a white trouser suit while meeting the Pope in June.
© POOL/AFP via Getty ImagesOther women granted the honour include Queen Mathilde of Belgium, Princess Marina of Naples, Queen Letizia of Spain, and Grand Duchess Stephanie of Luxembourg.
Two former queens, Queen Paolo of Belgium and Queen Sofia of Spain, are also allowed to wear white. Usually, the look is also accompanied by a lace mantilla.
Princess Charlene's most recent meetings with the Pope
Princess Charlene has already invoked the privilege this year for Pope Leo's visit to the Principality of Monaco back in March
She was seen wearing white as she stepped out to welcome the pontiff on the tarmac of Monaco Heliport.
© GettyLater, she opted for a bespoke Elie Saab coat dress featuring a tie belt waistline and a shin-skimming skirt. She wore a white Elie Saab dress underneath, as well as white stilettos and a white mantilla, in accordance with tradition.
Charlene's daughter, 11-year-old Princess Gabriella, joined her at the mass and twinned with her mother in white, also wearing Elie Saab, while her twin brother Jacques wore a smart suit.
