Camilla, who celebrates her 75th birthday next Sunday, described how much she enjoyed working with Kate on the shoot in her upcoming ITV documentary, Camilla's Country Life.
"She did really good pictures and you know she does it very naturally… we had a lot of fun doing it," Camilla said.
WATCH: Prince William and Kate view stunning portrait of themselves
"It was very relaxed and of course very kind of the Duchess of Cambridge… she's an extremely good photographer and it was all very casual, there wasn't much hair and make-up – it was just done in the garden with a lot of laughs – it was a lovely way of doing it."
The magazine asked Prince Charles' wife to edit the publication to mark its 125th anniversary and her milestone birthday, and in turn, she commissioned Kate to take two portraits of her for the special issue.
The Duchess is featured on the cover of Country Life and also commissioned articles for the special issue
The photos were taken in the gardens at Ray Mill House, Camilla's Wiltshire retreat, which she bought after divorcing her first husband Andrew Parker Bowles in 1994.
Kate photographed Camilla smiling down the lens with a trug filled with pelargoniums, while she sat on a bench surrounded by the lush greenery of her country estate.
The Duchess says that she enjoyed the laidback, 'relaxed' shoot
This is not the first time the Duchess of Cambridge has taken official portraits for a special occasion, however: she usually acts as royal photographer for her own children Prince George, Princess Charlotte and Prince Louis to mark their birthdays, first days at school, and other important milestones.
Kate is also the patron of the Royal Photographic Society and a keen amateur photographer, but this was the first time she photographed Camilla for an official magazine shoot.
Make sure you never miss a ROYAL story! Sign up to our newsletter to get all of our celebrity and royal news delivered directly to your inbox.