The royal couple’s attendance at the nuptials was kept under wraps until the last minute, when they were spotted walking through the bar of a five-star hotel in the capital Amman on Wednesday evening.
Just hours before the wedding ceremony on Thursday, Jordanian state media confirmed the British royals would be attending.
Catherine, the Princess of Wales, who lived in Jordan as a child, is understood to have become close to the groom’s mother Queen Rania.
And the Jordanian royal family have strong ties to the British royals, with King Abdullah and Queen Rania at the coronation in London last month.
They join a host of guests from royal families across Europe and Asia, including Spain, the Netherlands, Belgium, Denmark, Sweden, Norway and Japan.
US First Lady Dr Jill Biden and former US Secretary of State and current US climate envoy John Kerry are also attending the ceremony.
Jordan’s heir to the throne Crown Prince Hussein will marry 29-year-old architect Rajwa Alseif on Thursday afternoon at Zahran Palace in Amman in an “elegant and understated religious ceremony”, the Royal Hashemite Court said.
The venue played host to the wedding of King Abdullah and Queen Rania in 1993.
After the ceremony, the wedding party will move to Al Husseiniya Palace, a 30-minute drive away, for a reception, entertainment and a state banquet, where there are expected to be more than 1,700 guests.
The marriage is being seen as an opportunity to emphasize continuity in the Arab state after a rift between the King and his half-brother, present the 28-year-old crown prince to a wider global audience and forge a strategic bond with its oil-rich neighbour Saudi Arabia.
Noura Al Sudairi, an aunt of the bride, said: “We are all so excited, so happy about this union.
“Of course it’s a beautiful thing for our families, and for the relationship between Jordan and Saudi Arabia.”
It is also a welcome respite for many from the country’s economic difficulties.
Osama, a 25-year-old bookseller in Amman, told the Associated Press: “Of course, it’s joyful. But in a couple days, we’ll just go back to our problems.”
Excitement over the nuptials, Jordan’s biggest royal event in years, has been building in Amman, where banners of the groom and bride adorn buses and hang over winding hillside streets and shops display royal regalia.
The kingdom of 11 million citizens has declared Thursday a public holiday, with huge screens set up nationwide so people can watch the occasion unfold, crowds have gathered to wave at the couple’s motorcade of red Land Rover jeeps after the wedding and tens of thousands of well-wishers are also expected to flock to free concerts and cultural events during the day.
“It’s not just a marriage, it’s the presentation of the future king of Jordan,” said political analyst Amer Sabaileh. “The issue of the crown prince has been closed.”