Now, a jewellery expert has cautioned the Queen over the dress code she chooses while meeting the pontiff, as well as speculated the type of jewellery she would most likely wear.

Tobias Kormind, MD and Co-Founder of jewellers 77 Diamonds, said: "Royal visits to the Papal See require royals to adhere to a strict dress code rooted in tradition, respect, and protocol, with jewellery playing a significant role in their ensembles."

"In 1980, Queen Elizabeth II made history as the first British monarch to visit the Vatican, marking the occasion with the stunning Vladimir Tiara.

"Its magnificent pearl drops added elegance and regal presence to her look, perfectly complementing her black taffeta gown and mantilla veil.

"Jewellery has long been an essential element of royal attire for such visits, enhancing both symbolism and style."

The expert added on Queen Camilla: "For a meeting with the Pope, Queen Camilla would have to follow Vatican protocol by wearing a long black dress with long sleeves and a black mantilla.

"Rather than a tiara, Camilla might opt for a meaningful brooch, possibly a piece with religious significance or a historic royal connection.

"Pearl earrings or a pearl choker could complement the ensemble, reflecting her signature style."

The King and Queen will arrive in Rome on Monday, April 7, for an official welcome before undertaking engagements in the Vatican on Tuesday to celebrate the 2025 Jubilee.

Traditionally held once every 25 years, the Jubilee is a special year for the Catholic Church, and this year’s theme is: ‘Pilgrims of Hope’.

Charles and Camilla will celebrate their 20th wedding anniversary in Rome with a ceremonial welcome at the Palazzo Quirinale. The event will feature a special joint flypast over Rome by the Italian Air Force aerobatic team, ‘Frecce Tricolori,’ and the Red Arrows to symbolise the two countries' close defence relationship.

Their special day will also include a visit to the city’s iconic Colosseum, the Tomb of the Unknown Soldier, a visit to the Italian Parliament and a black-tie state banquet.