It has long been believed that King Charles planned for a slimmed-down monarchy during his reign.
But the number of working royals has been reduced significantly in recent years - not least due to the stepping back of Prince Harry and Meghan Markle.
The couple stunned the world when they announced their intention to quit their royal roles and carve out a new life for themselves in America.
It inevitably meant that other royals had to step up to help take on what would have been their workload - and according to one royal expert, one couple has done this more than most.
Former BBC royal correspondent Jennie Bond says it has been the Duke and Duchess of Edinburgh, who have been affected most by Harry and Meghan quitting.
And even though they have long worked hard for the Crown during their time as working royals - Jennie believes they are now playing a more "central role".
She told OK!: "Arguably, the departure of Harry and Meghan has affected the lives of Edward and Sophie more than anyone else.
"They have always done their fair share of royal engagements, but now, as Duke and Duchess of Edinburgh, they are recognised as senior and key members of the royal family.
"Their children are older than William and Catherine's, so they don't feel quite the same pressures to be home with their kids. They really are playing a central role in the new, slimmed-down royal family."
It comes as Sophie in particular has seen her profile rise recently after championing several hard-hitting causes.
Last month, it was revealed she had made a surprise visit to Iraq as part of her work championing the survivors of conflict-related sexual violence.
Sophie has spent two days in the capital Baghdad, where she heard about the challenges facing Iraqi women and girls, and the ongoing work to protect and promote their rights, Buckingham Palace announced.
The previously unannounced trip, which was kept secret for security reasons, was made at the request of the Foreign, Commonwealth and Development Office, in support of the Women, Peace and Security Agenda (WPS), the Palace said.
The Foreign Office advises against all travel to the majority of provinces in Iraq, amid the threat of violent protests in and around the International Zone in Baghdad.
Sophie visited a high school for girls and spoke to students and teachers about education for young women in the country and their hopes for the future.
She also visited a family planning centre to hear about work being carried out to support the reproductive health and wellbeing of Iraqi women and met female business leaders to discuss the importance of women's economic empowerment.
