Alex, 42, captioned her picture, suggesting she thinks the Duchess of Sussex has already given birth.
"Their Royal Highnesses have taken a personal decision to keep the plans around the arrival of their baby private".
"The Duke is now scheduled to travel to The Hague on Thursday 9th May for the launch of the Invictus Games The Hague 2020 as planned".
Media and well-wishers were camped out in Windsor on Saturday - as they have been for days - awaiting the birth of the couple's first child.
Prince Harry's change of itinerary prompted royal watchers to believe the royal baby has already arrived.
As the wait for news of the Royal baby continues, speculation that the baby is on its way has reached an all-time high, as Prince Harry has cancelled the first day of his trip.
North Korea launches missile
The JCS initially identified the projectiles as "short-range missiles" and shortly later modified its statement. North Korea said last month that it had tested a new type of unspecified "tactical guided weapon".
His visit to The Hague on May 9 will be "under review" depending on whether Meghan gives birth, royal correspondent Victoria Murphy reported.
In a statement Kensington Palace previously said: "The Duke and Duchess of Sussex are very grateful for the goodwill they have received from people throughout the United Kingdom and around the world as they prepare to welcome their baby".
After their stunning wedding previous year, the Duke and Duchess of Sussex, Prince Harry, and Meghan Markle gave another happy news when it was announced that the latter is pregnant.
Until the next baby Sussex update! Reportedly the Duke of Sussex will undertake a two-day trip to the Netherlands next week, Buckingham Palace has announced. While there, he will launch the countdown to the Invictus Games The Hague 2020.
Meghan, who is around nine months pregnant, revealed her due date will fall around the end of April to beginning of May.