In an elegant white ensemble, Princess Charlene of Monaco meets Pope Francis

Princess Charlene of Monaco joined husband Prince Albert for a Monday (Jan. 18) meeting with Pope Francis I, for which the stylish royal slipped into an elegant winter-white ensemble. The custom of wearing white during an audience with the Catholic leader is known as the "privilège du blanc" rule.

Only a handful of designated Catholic queens and princesses are permitted to wear white and Charlene is one of them, along with Queen Letizia of Spain, Queen Sofia of Spain and Queen Mathilde of Belgium.

Honouring the tradition, Charlene wore a white dress, a tailored white coat and a white lace veil to cover her hair. She completed her pristine look with a white clutch bag, white gloves and nude heels and added just a pop of colour with her red lipstick.

TAP TO VIEW GALLERYPrincess Charlene of Monaco looked pristine in white, adhering to the "privilège du blanc" rule.

During the private audience at the Apostolic Palace, the 37-year-old princess greeted the leader by bowing down and holding his hand to her forehead.

Charlene and Albert then exchanged gifts with Pope Francis and the trio spoke while aides watched on.

The mom of twins Jacques and Gabriella added a pop of colour to her look with lipstick.

There was no doubt that the religious leader and the royals had a lot to talk about. The last time they met was in 2013 during Pope Francis's inauguration mass.

At the time, Charlene wore black, the colour that protocol for papal audiences formally requires that ladies wear, along with a black mantilla. Michelle Obama obliged when she met Pope Benedict XVI in 2009 with her husband U.S. President Barack Obama.

Charlene and Prince Albert had a private audience with the Pope.

However, wearing black is not a strict requirement for all women. The Queen, who is the head of the Church of England, has met Pope John Paul II and Pope John XXIII in the past and both times she did not adhere to the rule.

Charlene's most recent high-profile outing with her husband took place in December, a few days before Christmas. The pair gave out gifts for children at the palace.

The last time Charlene met the Pope was in 2013, when she wore black.

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