To celebrate the announcement, the Duchess stopped by Warren Park Children's Centre in Kingston-upon-Thames, south west London for a photography workshop run by the Royal Photographic Society and Action for Children, another of Kate's' patronages.
The mother-of-three made the most of the balmy British weather in a light paisley print dress from Ridley London.
The Duchess teamed the pretty frock with her favourite pair of Castaner 'Carina' wedges and a dainty pair of gold leaf earrings from Catherine Zoraida, Daily Mail reports.
An enthusiastic amateur photographer, Kate, 37, often gets behind the lens to take artistic shots of her and Prince William's three children, Prince George, 5, Princess Charlotte, 4 and one-year-old Prince Louis.
In April, the Duke and Duchess of Cambridge took to their official Instagram account, Kensington Royal, to share two stunning photos of little Louis taken at their Norfolk home, Anmer Hall, to mark his first birthday.
One week later, the Duchess returned to social media to share a series of snaps of her only daughter Princess Charlotte in the garden of Anmer Hall.
The British Sun revealed the Duke and Duchess of Sussex refused to be "controlled" by the Duke of Cambridge, and have taken the decision to bow out of the charity founded by Prince Harry and William in 2009 because they "won't slot in line".
Initially dubbed the 'Fab Four', William and Kate first sparked whispers of disharmony with Harry and American-born Meghan shortly after the Sussexes' fairytale royal wedding at Windsor Castle in May last year.