Kate Middleton's Condition Is Shrouded in 'Radio Silence,' Palace Insider Says (Exclusive)

When Prince William abruptly pulled out of a planned outing to his godfather King Constantine of Greece's memorial service on Feb. 27, concerns surrounding Kate Middleton's health following abdominal surgery reached a fever pitch.

Despite the palace's brief comment stating that the Princess of Wales, 42, "continues to be doing well" in her recovery, and her recent sighting during a car ride with her mother, Carole Middleton, this week, one palace insider describes the overall lack of information as complete "radio silence" regarding her condition.

Kensington Palace revealed on Jan. 17 that Princess Kate underwent a "planned" abdominal procedure the previous day without giving further information on the cause, noting the royal's "wish that her personal medical information remains private." They did note that the issue was non-cancerous and that Kate wasn't expected to return to public royal duties until after Easter.

However, the lack of clarity about what led to the Princess of Wales' abdominal surgery left a vacuum that has been filled with numerous conspiracy theories regarding her health and whereabouts. In response to this speculation, a spokesman reiterated on Feb. 29 that Kate would not be resuming public engagements until after Easter.

"We were very clear from the outset that the Princess of Wales was out until after Easter and Kensington Palace would only be providing updates when something was significant," the spokesperson said.

Still, Princess Kate's presence is sorely missed, and Prince William has regularly received well wishes for his wife during his recent royal engagements.

"She is their MVP, without any doubt," royal historian Amanda Foreman tells PEOPLE exclusively in this week's cover story. "She is in so many ways the most like the late Queen."

Adds royal biographer Sally Bedell Smith, "She's so central to the monarchy and the future."

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Princess Kate's absence is exacerbated by King Charles also being largely out of the public eye as he receives cancer treatment. Similar to his daughter-in-law's health, there have been few updates about the King's condition.

"Everybody feels unsettled by uncertainty, and there is too much uncertainty that is surrounding the monarchy right now," Bedell Smith tells PEOPLE.

"Queen Elizabeth used to say, 'I need to be seen to be believed.' It is important for Charles and his reign for the public to know a little bit more," she adds.

In addition to two of the most senior members of the royal family being sidelined due to health concerns, Prince Harry and Meghan Markle's decision to step back from their roles as working members of the royal family in 2020 has left the royal family with few members to take up duties.

Adds Catherine Mayer, who authored the biography Charles: The Heart of a King: "This is massively exposing how the royal family has gone from too many people to too few in a short space of time."