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.
More top news
Foreign criminals are costing the UK £850m, with the number jailed or deported remaining broadly unchanged since 2006, according to a report
Toys R Us has scrapped its four collectible dolls based on the characters of the hit TV series Breaking Bad after a campaign by a US mother
Late actress Lynda Bellingham shared how she planned to spend Christmas during a moving final interview on Loose Women to be broadcast later