Kate will attend tonight's show in her role as an official ambassador of Britain's Olympic and Paralympic team, St James' Palace said.
A spokesman said:
The Duchess of Cambridge will tonight attend the BBC's Sports Personality of the Year awards at the ExCeL London, where Her Royal Highness will present the Lifetime Achievement and the main Sports Personality of the Year awards.
The Duchess will attend the event in response to a long-standing invitation from the BBC.
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