The Duke of Cambridge toured the spectacular archaeological site of Jerash on Monday – where the duchess was photographed with her father Michael and sister Pippa in the 1980s when the Middletons lived in Jordan.
He was shown around by Crown Prince Al Hussein bin Abdullah II during the second day of his five-day visit in the Middle East.
When he reached the spot where the picture of the Middletons was taken, he stopped and looked at a 2ft by 3ft enlargement of the image, released just before the Cambridges married in 2011.
The prince laughed and said: “Michael’s looking very smart in his flip-flops.”
He smiled and added: “Need to come back with the family for this shot.”
Kate’s family moved to Jordan in May 1984 when she was two and her sister was eight months old.
Their father, a British Airways manager then, relocated to the Jordanian capital of Amman for work.
The duchess went to an English language nursery while her parents were in the country for almost three years, before they returned to Berkshire in 1986.
William and Crown Prince Al Hussein bin Abdullah II met and were photographed by refugee Syrian mothers and their children, taking part in a photography workshop.
They are being supported by the Makani programme, a nationwide charity that works with people from deprived backgrounds, particularly refugee communities.
The Duke of Cambridge chatted with one mother through an interpreter, asking her about her background and her hopes for the future, telling her: “I hope one day you go back to Syria.”
He asked one child who came up to him her age, and she told him she was five, he replied: “My little boy is called George, he’s five as well.”
Some older children performed a welcome dance for the royals and the pair were also shown some of their artwork before leaving.