"The Duchess of Cambridge this morning held a Meeting of experts convened by the Royal Foundation of The Duke and Duchess of Cambridge and The Duke and Duchess of Sussex to inform Her Royal Highness's charitable "Early Years" initiative," a statement read.
The meeting was a private engagement meaning that no photographs were taken and it was not announced until after it had taken place.
The Early Years initiative is part of the duchess' campaign to help children failed by ‘Broken Britain’.
Kate is bringing together experts from academia, education, health and other fields to work on how to help families tackle anti-social behaviour, addiction and mental health.
Pippa and her husband James Matthews welcomed their first child, a baby boy, on Monday.
The little boy is the cousin of Kate and husband Prince William's children - Prince George, five, his brother Prince Louis, five months, and their sister Princess Charlotte, three.