The Duchess of Cambridge has made a private visit to a national conference on children's mental health.
Kate joined delegates during a coffee break at the event in east London, run by the Anna Freud National Centre for Children and Families (AFNCCF), a mental health charity she supports as patron.
It is understood the Duchess wanted to attend the day-long event as a delegate and listen to keynote speakers discussing an ambitious £56 million project that aims to explore and test new ways to improve young people's mental health and wellbeing.
Called HeadStart the five-year initiative has been funded by the National Lottery to tackle psychological problems faced by 10 to 16-year-olds by exploring and testing ways to build their resilience from an early age.
A Kensington Palace spokeswoman said: "During the conference, the Duchess will have the chance to meet with young people and staff leading the ground-breaking HeadStart programme which focuses on building mental health and resilience in children and young people across the country.
"Her Royal Highness will also hear keynote speakers from the field of resilience research; reflecting her interest in early intervention in children's mental health to help young people get support at an early age to prevent problems getting bigger later in life."
Kate's private visit to a public event is not unusual for a member of the royal family.
It is known that the Prince of Wales and Duchess of Cornwall attend the theatre and opera, and every year the Queen mingles with the public at the Royal Windsor Horse Show, as a visitor.