The 16th spot on the cover has been left blank, at the Duchess’s request, to represent a mirror designed to “include the reader and encourage them to use their own platforms to effect change.”
The Duchess of Cambridge appeared on the cover of Vogue in 2016 to celebrate its centenary, in collaboration with the National Portrait Gallery.
She was the most senior royal to grace the cover since Diana, Princess of Wales, who featured four times, including a posthumous appearance in October 1997.
The Princess Royal also appeared on the magazine’s cover, in 1971. The Queen, the Duke of Windsor, the Prince of Wales and Princess Margaret have also featured inside.
Mr Enninful said he was “delighted” that the Duchess had become the first person to guest edit the September issue, traditionally the biggest and best-selling and heralding the start of the fashion season.
“To have the country’s most influential beacon of change guest edit British Vogue at this time has been an honour, a pleasure and a wonderful surprise,” he said.
“As you will see from her selections throughout this magazine, she is also willing to wade into more complex and nuanced areas, whether they concern female empowerment, mental health, race or privilege.
“From the very beginning, we talked about the cover – whether she would be on it or not. In the end, she felt that it would be in some ways a ‘boastful’ thing to do for this particular project. She wanted, instead, to focus on the women she admires.”
In 2009, a documentary film called The September Issue gave a behind the scenes look as US editor-in-chief Anna Wintour and creative director Grace Coddington worked together on the 2007 US edition of the magazine.