The Duchess of Cambridge ran around in five-inch high heels playing volleyball with members of the SportsAid charity, during a visit to the copper box arena in the former Olympic Park in east London.
In her first solo public appearance since Prince George was born in July, Kate wore a casual outfit featuring a striped top, dark jacket, matching skinny jeans to see how Olympians and Paralympians are helped by SportsAid, which gives young athletes a financial boost and other practical help at the start of their careers.
The Duchess is patron of SportsAid and was an official ambassador for Britain's London 2012 teams. SportsAid helped 20 of the 29 Olympic gold medallists from London 2012 and 27 of the 34 Paralympic gold winners.
Sport stars supported by the charity include cyclists Sir Bradley Wiggins and Sir Chris Hoy, heptathlete Jessica Ennis, diver Tom Daley, double Olympic gold medallist Rebecca Adlington, wheelchair racer David Weir and Paralympic swimmer Ellie Simmonds.
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 from 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.