Since Prince George's birth in July, the Duchess of Cambridge has rarely been seen in public as she adjusts to life as a mother.
In September, Prince William and Kate spent their first night away their son to attend a black-tie awards ceremony.
The Duchess had previously made her first surprise public appearance since George's birth when she joined her husband as he started the Anglesey Coastal Ultra Marathon in August.
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The TV sports presenter has arrived back in the UK where she will be making her recovery in St James Hospital in Leeds.
HMS Enterprise assisted with saving more than 6,500 migrants off the coast of Libya on Tuesday.
Abu Muhammad Al-Adnani, cited as so-called Islamic State's official spokesman, was reported as killed in Syria by the group's media branch.