Meghan and Harry set up their own Instagram in April 2019, having previously shared the Kensington Palace account with William and Kate.
And they are on course to overtake the Cambridges with the two accounts now both on 11 million followers.
It comes after Meghan and Harry revealed plans to step back as senior royals in a bombshell statement earlier this month.
The shock move promoted crisis talks between the Queen, Prince Charles, William and Harry.
In a statement issued on Saturday, it was announced that the Sussexes will stop carrying out royal duties from the spring, no longer use their HRH titles and repay the £2.4 million of taxpayers’ money spent on Frogmore Cottage.
Meghan and Harry had wanted to stay on as working royals but become financially independent.
However commentators warned the dual role would be problematic.
The latest Sussex Royal Instagram post shows Harry pictured with Morocco’s Prime Minister Saad-Eddine El Othmani, Malawi’s President Peter Mutharika and Mozambique’s President Filipe Nyusi.
In a speech at an event for his charity Sentebale on Sunday night, Harry spoke out about his decision to quit royal life.
He said: “What I want to make clear is we’re not walking away, and we certainly aren’t walking away from you.
“Our hope was to continue serving the Queen, the Commonwealth, and my military associations, but without public funding. Unfortunately, that wasn’t possible.
“I’ve accepted this, knowing that it doesn’t change who I am or how committed I am.
“But I hope that helps you understand what it had to come to, that I would step my family back from all I have ever known, to take a step forward into what I hope can be a more peaceful life.”
Harry has now returned to Canada after concluding royal talks on his and Meghan’s future roles.
Photographs showed him getting off a plane at Vancouver International Airport and into a waiting car.