Kate was visiting the garden centre in Norfolk, England for her first in-person appearance since the UK went into lockdown due to the coronavirus crisis.
But despite being one of the most famous members of the royal family, it appears the couple didn’t know who she was.
"A lot of the customers at this garden centre didn't recognise while she was walking around,” podcast host Rachel divulged.
“There are hilarious pictures of her and I think a video of a clip of her saying a lot of people are buying herbs today," she added.
"Then this elderly couple are like 'yes', and wondering, 'why is this person is talking to us' and then walked away."
Rachel added that the pair were only alerted to their brush with royalty when approached by the press after the encounter.
She revealed: “They later said to the press, it was the Duchess of Cambridge and we had no idea and we felt like we brushed her off completely.”
Despite the awkward snub, the ever-poised Kate apparently took it in her stride and simply smiled and politely walked away.
Mum-of-three Kate is currently in lockdown with her husband Prince William and their three kids, George, six, Charlotte, five, and Louis, two, at their country home in Norfolk.
During the visit to the garden centre, green-fingered Kate revealed how much her children have taken to gardening, particularly enjoying growing tomatoes.
"They were very excited to grow them from seeds and now they're as tall as them," Kate said, as reported by Hello! magazine.