However, the post was accompanied by a delighting wish from the Duke who wished Markle with this message.
"It is testament to Meghan that she has been given this invite".
"Thank you to the Duke and Duchess of Cambridge for always being a class act", another wrote.
Harry reportedly whisked Meghan away for a romantic break in Africa to mark her 36th birthday, flying to Botswana.
William and Kate's birthday tribute for Meghan read, "Wishing a very happy birthday to The Duchess of Sussex today!" He added that the Duchess of Sussex declined because it was a "boastful thing to do".
Trump has 'no problem' with latest North Korean missile tests
Hours later, Pyongyang said it never has, and never will, recognize the Security Council's resolutions. The North also tested short-range missiles on May 4 and 9.
Clarence House, which is the social media account for Prince Charles and his wife Camilla, the Duchess of Cornwall, also posted a special message to the 38-year-old. Instead of a home in Norfolk near Anmer Hall - the country home of Prince William and Kate Middleton - Dampier says it would make more sense for Harry and Meghan to have their second home in the Cotswolds.
The Duke of Sussex posted a loving message to his wife on the couple's Sussex Royal Instagram account - and our hearts just melted.
Harry has a history of going to great lengths to celebrate Meghan's birthday.
The Duke shared his loving words with the couple's 9.2million followers alongside a handsome photo of Meghan, which was taken past year at the Queen's Commonwealth Canopy in Tonga.
Their public displays of affection have broke many years of royal tradition.