Princess Eleonore, 15, of Belgium steps out in all-black outfit as she enjoys a night at the opera in Brussels with her mother Queen Mathilde

Princess Éléonore and Queen Mathilde were the most elegant mother-daughter duo as they stepped out for a night at the opera today.

The royal duo were photographed attending the opera ‘Cassandra’ at the Opéra de la Monnaie in Brussels, alongside its director Peter De Caluwe.

Queen Mathilde, 50, looked elegant in a structured gold top with black floral detailing and matching black flared pants.

She accessorized the look with a dazzling pair of gold floral earrings, a gold clutch and pointy black pumps.

For her makeup, a bold red lip was the perfect choice for the evening festivities, as was her black eyeliner and perfectly styled blonde bob.

The 15-year-old (pictured, left) wore a chic all-black ensemble as she attended the event with her mother, Queen Mathilde (pictured, right).

During the opera, it seemed that Queen Mathilde was explaining something to her daughter, who seemed to be listening attentively to her mother.

The mother and daughter appeared to be deep in conversation at one point and appeared to be enjoying each other’s company.

Meanwhile, her daughter Princess Éléonore, who celebrated her 15th birthday in April, has scaled back her glamor slightly.

She opted for a black sleeveless top and pants, which she paired with black patent leather flats.

Unlike her mother, she chose to stay casual by omitting accessories, jewelry or the matching bag.

Her makeup was subtle in nature, letting her natural beauty shine through.

Queen Mathilde’s appearance comes about a week after her visit to Vatican City with her husband King Philip. for a private audience with Pope Francis.

There, the Queen wore a modest white dress for the occasion, which reached just below the knee, paired with a white mantilla which she wore draped over her head.

Black lace is customary during the Pope’s visit – only a handful of people are allowed to wear white around the religious figure during their visit to the Vatican.

Only seven women in the world are allowed to wear white in front of the Pope.

The royals are pictured sitting next to De Munt-La Monnaie chief executive Peter De Caluwe (pictured right).

The opera watched by the two members of the royal family, “Cassandra”, is a work by the Belgian composer Foccroulle

Princess Éléonore, Queen Mathilde of Belgium and the general director of De Munt-La Monnaie Peter De Caluwe are pictured at the De Munt Opera – La Monnaie in Brussels

During their outing to the opera, the royal couple (photo, left) also spoke with musician and composer Bernard Foccroulle (photo, right).

These include Charlene, Princess of Monaco, Queen Letizia of Spain, Queen Mathilde of Belgium and Maria Teresa, Grand Duchess of Luxembourg.

“White privilege” also extends to Queen Paola of Belgium and Princess Marina of Naples.

The privilege only extends to these royals because they are the seven Catholic queens, princesses and duchesses.

This meant that when Queen Camilla visited the Pope, she had to wear black, as she had never converted to Roman Catholicism, despite growing up in a Catholic family.

Instead, she is Anglican.