The Duchess of Cambridge will attend the BBC's Sports Personality award show tonight in her first public engagement since leaving hospital for severe pregnancy sickness, St James' Palace said.
She will present the main award and lifetime achievement honour when Britain's top sports stars gather to celebrate a year of sporting achievement hailed as the nation's greatest ever.
The Duchess has not been seen in public since leaving the King Edward VII's Hospital in London on December 6.
She had received three days of treatment for a condition known as hyperemesis gravidarum, which leaves expectant mothers so ill they cannot keep food or liquids down.
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."
Kate, who is less than 13 weeks pregnant, was ordered by doctors to have a period of rest at her home at Kensington Palace after leaving hospital.
She was recently forced to miss two royal engagements - a Centrepoint Royal Albert Hall fundraiser and the British Military Tournament.
The Duke of Cambridge will not attend the event at London's ExCel centre as he remains in Anglesey in his role as an RAF search and rescue helicopter pilot, a St James' Palace spokesman said.
Olympic and Paralympic heroes dominate this year's Sports Personality shortlist, with golfer Rory McIlroy the only one of the 12 nominees not to have won medals at London 2012 this summer.
Cyclist Bradley Wiggins is the bookmakers' odds-on favourite after his historic triumph in the Tour de France and gold in the Olympics time trial, followed by heptathlon champion Jessica Ennis.
The Duchess' public diary is likely to be tailored to how she is coping with her condition, which causes prolonged bouts of vomiting triggered by smells and even movement.
She looked well and even smiled briefly as she posed with the Duke for the world's media after leaving hospital.
When a member of the press asked how she was feeling, the Duchess, wrapped up against the cold in a coat and scarf and carrying a bouquet of yellow flowers, replied: "Much better."