Prince William traveled to Paris just hours after attending Kate Middleton’s annual Christmas carol concert at Westminster Abbey with their children to take part in the highly anticipated reopening of Notre Dame Cathedral.

On Saturday, Dec. 7, the Prince of Wales, 42, represented his father, King Charles as the monarch continues his cancer treatment. William joined world leaders and heads of state — including French President Emmanuel Macron, First Lady Jill Biden, and U.S. President-elect Donald Trump — at the ceremony celebrating the restoration of the iconic Gothic cathedral.

Due to difficulties caused by the weather, Prince William met Biden, 73, at the ceremony rather than beforehand, as initially planned, and met with Trump, 78, after.

This marks the second major occasion this year where William has stepped in for his father in a diplomatic role. In June, he represented King Charles, 76, during the Second World War commemorations marking the 80th anniversary of the D-Day landings. Buckingham Palace cited medical advice at the time for the King’s absence, though it has yet to address why William attended Notre Dame’s reopening instead of his father.

King Charles previously visited the cathedral during a state visit to France last year, where he was shown the craftsmanship involved in the cathedral’s restoration.

Prince William’s most recent visit to Paris was in 2017 when he and Kate spent two days in the French capital.

The iconic Notre Dame Cathedral, located along the River Seine in Paris, was devastated by a massive fire five years ago and has since undergone an extensive and impressive restoration. The blaze, which occurred on April 15, 2019, left the historic landmark severely damaged. On Nov. 29, President Macron unveiled the newly restored cathedral during a televised tour, as reported by NBC News.

On Dec. 6, William was joined by Prince George, 11, Princess Charlotte, 9, and Prince Louis, 6, at Kate’s fourth annual Together at Christmas carol service. It marked the first public appearance of the three siblings together since Trooping the Colour in June.

In a candid moment, Kate reflected on her challenging year after being diagnosed with cancer, telling carol concert performer Paloma Faith, “I didn’t know this year was going to be the year that I’ve just had.”

“The unplanned,” Faith said.

“The unplanned, exactly,” the Princess of Wales repeated, nodding her head, adding, “But I think lots of people this year have had such challenging times, and many who are here today.”