The beloved royal, who has been battling severe morning sickness during her second pregnancy, has pulled out of an event scheduled for next Monday, Oct. 13. Middleton, 32, had planned to be in Portsmouth, England, next week to visit Olympic sailor Sir Ben Ainslie's America Cup team base.
"She had plans to go to the team's new headquarters in the Camber Docks at Old Portsmouth," the source tells Us. "The engagement was never formally announced."
Due to her physical ailments, the Duchess will no longer be keeping the engagement. This is one of many appearances that the stunning Brit has been forced to cancel.
After announcing her pregnancy with Prince William's second child last month, Middleton bowed out of her plans to make her first solo royal tour to Malta at the end of September.
"Her Royal Highness continues to suffer from the effects of hyperemesis gravidarum," the palace said in a statement at the time of Middleton's cancellation. "The decision not to visit was taken by the Duke and Duchess on the advice of the Duchess' doctors."
The Duchess also dealt with hyperemesis gravidarum during her first pregnancy with Prince George, now 14 months. The condition sent Middleton to the hospital to receive treatment, and she has been cared for at Kensington Palace by doctors as of late.
"The decision to undertake engagements is being kept under review on a case by case basis," a spokesman for Kensington Palace told Us Weekly in a statement.