The duchess was invited to oversee the edition by the title’s editor-in-chief, Edward Enninful, who said she turned down the opportunity to appear on the cover because she felt it would be “boastful”.

Instead, the front of the magazine will feature 15 women who are “trailblazing changemakers, united by their fearlessness in breaking barriers”, according to Buckingham Palace.

In keeping with the edition’s theme, which is “forces for change”, the duchess has assembled women including the actor Jane Fonda, the climate change campaigner Greta Thunberg, the prime minister of New Zealand, Jacinda Ardern, and the model Christy Turlington Burns.

Inside the magazine, Meghan, who has worked on the project for seven months, recounts a candid conversation between herself and Michelle Obama, and interviews the renowned ethologist and primatologist Dr Jane Goodall.

Meghan said: “These last seven months have been a rewarding process, curating and collaborating with Edward Enninful, British Vogue’s editor-in-chief, to take the year’s most-read fashion issue and steer its focus to the values, causes and people making impact in the world today.

“Through this lens I hope you’ll feel the strength of the collective in the diverse selection of women chosen for the cover as well as the team of support I called upon within the issue to help bring this to light.

“I hope readers feel as inspired as I do by the forces for change they’ll find within these pages.”

Enninful said Meghan was the first person to guest edit the September issue.

“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,” he added.

The September edition of fashion magazines is considered to be the most important of the year as they carry the most advertising and often feature iconic cover stars. Vogue’s 2012 issue with Lady Gaga on the cover ran to 916 pages and weighed 2.5kg.