The 33-year-old model - who previously dated Leonardo Dicaprio for five years until 2011 and has Liv, 22 months, and Elle, eight months, with husband Adi Ezra - met the 36-year-old royal as he made history as the first member of the royal family to visit Israel on am official engagement.
The pair were introduced at a party hosted at the private residence of UK ambassador Mark Regev, and the blonde beauty - who wore a floor-length red dress to the bash - admitted to taking a fancy to both William and his younger brother Prince Harry, who is the same age as her.
She said: ''He (William) is very, very charming.
''I think both he and his brother are good looking - but he is the best looking prince in the world.''
Whilst in the Middle East, William is set to visit Jordan, Israel and the Occupied Palestinian Territories.
Kensington Palace previously announced the tour was planned at the request of ''Her Majesty's government'', however it's not a political trip.
William did, however, meet with Israeli Prime Minister Benjamin Netanyahu and wife Sara Ben-Artzi.
The prince is on tour on his own, leaving his wife Duchess Catherine to look after their children Prince George, four, two-year-old Princess Charlotte, and two-month-old Prince Louis.
William said on behalf of his wife when he arrived in Jordan that Catherine was ''very sorry she cannot be here with me so soon after the birth of our son Louis''.
He added: ''Her family remembers very fondly the almost three years she spent here as a child when her father worked for British Airways in Amman''.