The Prince’s view, a close friend recently told The Times, is that Sophie and her husband, Edward, are ‘needed’ and ‘it’s really important that the fantastic work that they do is seen’. It’s said that both William and Kate are big supporters of the Duke and Duchess of Edinburgh, and are already raising their royal profiles. The Waleses reportedly deeply admire the couple’s quiet, dutiful approach to their roles, particularly Sophie’s determined championing of charities that work to combat sexual violence in conflict and support young people.

In December, Sophie was among those who joined the Princess of Wales for her annual carol service, beaming as she arrived for the Together at Christmas concert at Westminster Abbey. Poignantly, Sophie was given a seat of pride of place, sitting on Kate’s left-hand side for the concert. Ingrid Seward, royal author, described the women’s ‘sisterly bond’ to HELLO! and added that Sophie ‘has been there in the background [for Kate], as part of a private support network.’ Biographer Claudia Joseph, meanwhile, told The Sun that Kate has relied on the Duchess’ wisdom for years: ‘She has found that Sophie is a true confidante and sounding board and they have developed a mutual respect and an unbreakable bond.’

Given this burgeoning friendship, it’s little surprise that the Waleses have come to see the Edinburghs as crucial to the future King William’s court. During an engagement last month, the Prince and Sophie were deemed a natural double act as they visited the Royal Cornwall Show, where they sampled cider and whiskey and clearly enjoyed each other’s company. Last year, The Times reported that Sophie had more than doubled her workload compared to the previous year, as she was called upon to represent the family more than ever as the Princess of Wales stepped back to focus on her recovery.

So as the Duchess’s royal standing continues to rise, could it be time to forgo the ‘secret weapon’ label?