The Good Morning Britain presenter took part in the latest series of ITV’s DNA Journey, which uncovered she is a relative of the bear’s creator Michael Bond.
Kate and Michael’s daughter Karen Jankel were introduced on the forthcoming episode, and it was revealed they have the same three times great-grandparent.
The pair had an emotional meeting after coming face-to-face at the London train station that bears the character’s name.
Karen told Kate she wanted to introduce her to her “famous brother” before revealing a stuffed toy of Paddington Bear, complete with a travel tag reading “Darkest Peru”.
“Paddington and I grew up together,” she told her. “The reason is that my father was Michael Bond, the creator of Paddington, which means that of course you are also related to Michael Bond.”
Karen said of the marmalade-loving bear: “He was always part of my family. He is so real to our family, and now to your family too, because he is a member of the family.
“He used to sit on the table at meal times and my father used to talk to him and talk through him to us. Of course, I never knew anything else because he was always around.”
Karen also showed Kate her first edition copy of A Bear Called Paddington, signed by her late father in September 1959.
“It was always my absolute favourite growing up,” Kate said.
“It has been said to me over the years that I do have a touch of Paddington Bear about me and that is because without meaning to he does cause an extraordinary amount of chaos.”
The presenter also joked she used to regularly eat marmalade sandwiches during her time at university.
British author Michael Bond published more than 20 books featuring Paddington Bear before his death in June 2017 aged 91.
The enduring children’s book character famously arrived in London from Peru and first appeared in print in 1958 in the book A Bear Called Paddington.
DNA Journey also saw Kate visit Bristol alongside fellow TV presenter Alison Hammond to hear about her distant relative Frederick Lambert, her first cousin three generations removed.
He lived and worked as a photographer in the city during the 1840s while still a teenager.
DNA Journey airs on Thursday on ITV at 9pm.