(CNN) A few months ago, two of the highest-profile black women in America and Britain sat down over a chicken taco lunch and discussed a "secret project." The result: an interview between The Duchess of Sussex Meghan Markle and former first lady Michelle Obama in British Vogue, conveying a rarely seen sense of intimacy and friendship between the two women.

The Duchess of Sussex served as Vogue's guest editor for its famed September issue, which she has titled "Forces for Change," featuring a range of influential women leaders.

British Vogue traditionally features a Q&A-format piece on its last page, and, Markle said, she wanted "someone kind, inspirational, motivating, funny, with gravitas and as much depth as levity" to do the honor. Obama came to mind.

"So, over a casual lunch of chicken tacos and my ever-burgeoning bump, I asked Michelle if she would help me with this secret project," Markle wrote, calling her "my former First Lady, and now friend, Michelle."

In the interview, the women expressed a sense of familiarity with each other. The Duchess kicked off her questioning asking, "You sent me the kindest message on Mother's Day this year. What has motherhood taught you?"

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