A drinks reception and gala dinner was held on Thursday (October 23), for the 'Action on Addiction' charity in central London.
Wearing a black crocheted Temperley dress, the Duchess of Cambridge, who is a patron of the charity, walked the red carpet at the swanky L'Anima restaurant.
Comedian Rory Bremner is also expected to attend.
It was the Duchess of Cambridge's third public appearance in as many days, since the announcement was made that she is pregnant with her second child, which is due to be born in April.