The Royals

Kate & Lupo Walk Through Kensington Gardens with James Middleton

06/15/2012 at 07:20 AM EDT

Kate Middleton Walks Dog in Kensington Gardens

Kate and James Middleton with their dogs

Courtesy Jocelyn Laidlaw; Inset: Bauer-Griffin

It doesn't take much to bring Kate down to earth.

After days of buoyant Diamond Jubilee celebrations for Queen Elizabeth, the Duchess of Cambridge slipped into something more comfortable – jeans, Barbour jacket and a hat – and stepped out for a walk through Kensington Gardens with her dog Lupo, her younger brother James Middleton, and another dog, presumed to be a Middleton family cocker spaniel.

The siblings were spotted last week by Canadian TVjournalist Jocelyn Laidlaw in a chance sighting at Kensington Gardens in London.

"Catherine Duchess of Cambridge walking Lupo today in Kensington Gardens," Laidlaw wrote. "Lovely to see her so low-key. What luck."

PHOTOS: Lupo's Royally Awesome Life

A video posted by Laidlaw shows the Middleton pair walking briskly through the park, largely going unnoticed and left undisturbed. Both dogs trot along off-leash but stay close.

Kensington Gardens, a Royal Park of London, has been a go-to walk for the Duchess and her cocker spaniel puppy, who have been spotted on other occasions getting some fresh air on the grounds.