June 19 (UPI) -- The Princess of Wales unexpectedly pulled out of attending Royal Ascot at the last minute, with officials saying it was related to her recovery from cancer.

Kate Middleton skipped the Royal Family's traditional excursion to the event 30 miles southwest of London on Wednesday, which is a key fixture in the country's horse racing calendar.

The decision came amid efforts to strike a balance as she eases back into her public role as the wife of Prince William, Kensington Palace said.

An official told The New York Times she was "disappointed" not to be able to attend, adding that she needed to find the "right balance" in the level of public engagements she takes on.

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