British Pathe newsreels showing the Duchess of Cambridge's relatives during the early 20th century have been discovered.
Kate's illustrious forebears are featured in the black and white footage during the First World War period and just over a decade later.
The Duchess's great-great-great uncle Sir Charles Lupton, the lord mayor of Leeds, is featured paying a visit to the Leeds Pals Battalion in a camp near Colsterdale in the Yorkshire Dales.
In the newsreel from 1915 Sir Charles, wearing his chain of office, bowler hat, suit and overcoat, inspects the soldiers accompanied by an officer, and in one shot is followed by a large entourage.
He was joined by his three brothers, Arthur, Hugh and Kate's great-great grandfather Francis Lupton.
It is not known which man in the entourage was Francis but his name was noted down by the original cameraman.
Hugh Lupton followed in his brother's footsteps and also became lord mayor of Leeds, and in Pathe footage from 1927 Kate's great-great-great uncle and his wife Isabella are shown greeting the Queen's aunt Princess Mary.
Mary was in Leeds to inaugurate a girls' week campaign for Hunslet Young Women's Christian Association.
Fashions might have changed since the 1920s but royal visits remain largely the same, and the Princess was given a large bouquet of flowers as she left and her entourage drove off in chauffeur-driven limousines.
Alastair White, general manager of British Pathe, said: "We often get contacted by visitors to our website who are thrilled to find films of their ancestors, their close family or even themselves as youngsters.
"We knew we had many films of Prince William's family, but it was a real surprise to find that we also have the Duchess of Cambridge's ancestors and that they were meeting royalty."