Misan Harriman posted the photo after the couple announced they're expecting a baby girl in their sit-down interview with Oprah.
"She might be marrying into a family that could cause her some emotional complications," the "Last Week Tonight" host said in 2018.
“That brought back memories,” The Duke of Sussex told Oprah on Sunday.
The Duchess of Sussex and Duchess of Cambridge have often been pitted against each other in media stories.
The Duchess of Sussex told Oprah on Sunday, "I just didn’t see a solution."
The Duchess of Sussex also said her son with Prince Harry was not offered a title or protection by the British royal family.
The Duke and Duchess of Sussex dropped the wedding bombshell during their interview with Oprah.
The two-hour interview will air in Australia just hours after it hits screens in the US.
Fans said Frankel had "hit a new low" in comparing her reality TV career to Meghan's experience in the public eye.
The messages aired hours before CBS broadcasts the Duke and Duchess of Sussex’s highly anticipated tell-all with Oprah Winfrey.