Kate, who is more than eight months pregnant, will stay at home, but William and Harry are expected to be among the congregation to watch Thomas van Straubenzee marry Lady Melissa Percy.
The Duchess' final official public appearance was last weekend when she attended the Trooping the Colour ceremony with other members of the Royal Family.
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Temperatures will remain low for most of the country as Britain battles against wintry showers, snow and gales this afternoon.
A giant panda has been caught in camera breaking iron bars and moving into the other cell to have a taste of milk in the next cell.