London, UK - Princess Kate Middleton's recent appearance at Wimbledon will probably be her last public appearance this summer.

Since the Princess of Wales was diagnosed with cancer, public appearances have become a rarity.

After a month-long break, the royal appeared with her family at King Charles' birthday parade in London in mid-June, and last weekend she attended the famous tennis tournament at Wimbledon.

These will likely be her last public moments this summer, says Kate Middleton biographer Robert Jobson.

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"Before, she used to live her life by the calendar, and now she is living her life, and the calendar comes in after," he said.

Jobson is certain that the 42-year-old "will be back."

But he also reports, "When you have had an experience like this, it changes your perspective and the order of things

The royals are expected to spend the majority of the summer at their country home Ammer Hall in Norfolk, England, as well as a stay with King Charles at Balmoral Castle.

An insider from the palace told People, "She doesn't need to be in the spotlight. Being with her family and just being herself will give her energy. This will give her enough time to focus on her recovery."

According to the insider, she's "not out of the woods yet," but she is slowly taking on more duties at the palace.

"It’s good not to feel under pressure and just take her time," adds another palace source.