Kate Middleton’s next major royal glamour moment is officially on the calendar.

Buckingham Palace announced on Thursday, Sept. 3, that Sultan Haitham bin Tarik of Oman will make a state visit to the United Kingdom from Oct. 20 to 22, marking the first incoming state visit of the season — and setting the stage for another glittering night at Windsor Castle.

King Charles and Queen Camilla will host the Sultan during the three-day visit, which will traditionally include the full pageantry of a ceremonial welcome and a white-tie state banquet. While the palace has not yet announced the full lineup of royal family members taking part, Prince William and Kate are expected to play prominent roles, as they have during recent state visits.

For the Princess of Wales, the occasion could bring her next tiara appearance. State banquets are among the rare occasions when royal women wear tiaras, making them some of Kate’s most anticipated style moments of the year.

But William and Kate’s involvement in state visits has increasingly gone far beyond the glamour.

Over the past year, the Prince and Princess of Wales, both 44, have taken on a historic role at the heart of Britain’s royal diplomacy. As heir to the throne and future Queen, William and Kate have regularly been tapped to personally greet visiting heads of state and accompany them to meet King Charles and Queen Camilla — placing the couple front and center as the monarchy welcomes some of the world’s most important leaders.

Kate Middleton’s next major royal glamour moment is officially on the calendar.

Buckingham Palace announced on Thursday, Sept. 3, that Sultan Haitham bin Tarik of Oman will make a state visit to the United Kingdom from Oct. 20 to 22, marking the first incoming state visit of the season — and setting the stage for another glittering night at Windsor Castle.

King Charles and Queen Camilla will host the Sultan during the three-day visit, which will traditionally include the full pageantry of a ceremonial welcome and a white-tie state banquet. While the palace has not yet announced the full lineup of royal family members taking part, Prince William and Kate are expected to play prominent roles, as they have during recent state visits.

For the Princess of Wales, the occasion could bring her next tiara appearance. State banquets are among the rare occasions when royal women wear tiaras, making them some of Kate’s most anticipated style moments of the year.

But William and Kate’s involvement in state visits has increasingly gone far beyond the glamour.

Over the past year, the Prince and Princess of Wales, both 44, have taken on a historic role at the heart of Britain’s royal diplomacy. As heir to the throne and future Queen, William and Kate have regularly been tapped to personally greet visiting heads of state and accompany them to meet King Charles and Queen Camilla — placing the couple front and center as the monarchy welcomes some of the world’s most important leaders.

Princess Kate played a particularly prominent role during U.S. President Donald Trump‘s state visit to the U.K. She sat next to the Commander in Chief during the state banquet and seemed to charm him; Trump toasted her as “radiant and healthy” during his speech at the dinner.

Speaking exclusively to PEOPLE about the Princess of Wales’ impact during the visit, royal biographer Ingrid Seward said that the future queen was “very aware” of the spotlight on her.

“She lightened the whole evening. She lit up the table with the megawatt smile. There was a lot of pressure on her because all eyes were on her,” said the editor-in-chief of Majesty magazine. “She would be very aware that the most important person there was the King, but she can’t help that all eyes are on her.”

“She is definitely showing traits of being a remarkable future queen,” Seward added. “She has the most beautiful smile, which captivates everyone. It’s just magical.”

State visits offer the royals a chance to wield their all-important “soft power” as representatives — and gracious hosts — of the United Kingdom.

While they are intended to remain apolitical, the royals’ presence can create opportunities for dialogue and smooth the path for negotiations between actual policymakers.

The term was coined by American scholar Joseph Nye, who introduced it as a counterpoint to the idea that all influence is measured in military strength or economic might. He was inspired in part by a visit to the U.K., where he witnessed the soft power of the late Queen Elizabeth in full force.

Finding The Mall near Buckingham Palace closed for the Queen’s attendance at the State Opening of Parliament, Nye missed an appointment while “the crowd waited for a little old lady driven by a horse and carriage,” he wrote in A Life in the American Century.