There are denials that the decision not to invite the Duchess of York is a snub, when she has maintained good relations with her royal ex-in laws, including spending Easter with them this year.
When the late Queen died last year, the duke and duchess adopted two of her corgis.
The 63-year-old duchess shares a house with her ex-husband, almost 27 years after they divorced, although there have been reports of pressure for Prince Andrew to move out of Royal Lodge in Windsor.