The Duchess, 74, edited this month’s edition of the magazine to mark her forthcoming 75th birthday, following in the footsteps of her husband, the Prince of Wales, who has taken on the role twice.
Mark Hedges, editor of Country Life, revealed that the Duchess had asked if she could “have a go” at it herself some time ago.
When it was eventually agreed she would take charge of the July edition, the senior editorial team decamped to Clarence House for a meeting.
‘One of the most amazing things that could happen’
Mr Hedges said one of the most pressing issues was to ask whether the Duchess had any ideas for the all-important front cover.
“She immediately replied, ‘Oh I’d quite like Catherine to do it’,” he recalled.
“I spent the next three or four minutes desperately racking my brains trying to think of a professional photographer called Catherine.
“Then I suddenly grasped what she meant – one of the most amazing things that could happen. I found it one of the easier things to nod my head at.”
Mr Hedges said the resulting image showed just how close the two women were, the Duchess clearly at ease.
“I don’t think anyone else would have made her feel so relaxed,” he added.
“They didn’t bother too much with hair and make-up, they just got some flowers for the garden and got on with it.”
A royal aide said the Duchess had chosen her step daughter-in-law to take the images because she had long been impressed by her photography skills.
The Duchess of Cambridge, who is patron of the National Portrait Gallery, has increasingly released her own images to mark her children’s birthdays as well as those of other of members of the Royal family, including Prince William with Prince Charles, Prince George with the late Duke of Edinburgh and the Queen, the Duke and their various great grandchildren.