As the publication's guest editor to mark its 125th anniversary and Camilla's 75th birthday later this month, Prince Charles' wife commissioned Kate to take the cover photo.
Camilla is pictured sitting on a bench with a trug filled with pelargoniums, ready to be planted. Smiling and looking relaxed, the Duchess wears a blue and white floral dress and cardigan.
WATCH: Prince William and Kate view stunning portrait of themselves
Another picture by Kate appears on the leader page and is an informal shot of Camilla walking through forget-me-nots at her country home.
Kate, who is a keen amateur photographer and patron of the Royal Photographic Society, regularly takes the official portraits of her own children Prince George, Princess Charlotte and Prince Louis for important milestones such as birthdays and first days of school.
The magazine photos were taken in the gardens of Ray Mill House, Camilla's retreat in Lacock in Wiltshire. The Duchess purchased the six-bedroom property, 17 miles from Prince Charles' Highgrove estate, after her divorce from Andrew Parker Bowles in the mid 1990s.
Camilla guest-edited the magazine for her 75th birthday
Mark Hedges, editor-in-chief of Country Life magazine, said: "We are thrilled to have our guest editor captured so magnificently by royal photographer the Duchess of Cambridge.
"We understand this is the first time a formal portrait of the Duchess of Cornwall has been taken by the Duchess of Cambridge for a magazine and we are honoured to have been chosen to be the first to publish this beautiful photograph.
"The photographs are superb and we would be delighted to offer the Duchess of Cambridge another commission!"
Kate took the photos at Camilla's Wiltshire home
This is the first time Camilla has guest-edited the magazine, which is out on Wednesday, although her husband Charles has had the honour twice – in November 2013 to mark his 65th birthday and again in 2018 for his milestone 70th birthday which ended up being the biggest selling issue of all time.
In 2020, Princess Anne led the July 29 issue to commemorate her 70th birthday.
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