The message, recorded before last week’s announcement that the Duchess is expecting her third child, supports an initiative that aims to equip primary school children with the confidence to talk about their feelings or listen to friends when they need a sympathetic ear.
Kate is backing the You’re Never Too Young To Talk Mental Health campaign run by the Anna Freud National Centre for Children and Families, which she supports as patron.
As part of the initiative, the Duchess has also written the introduction to a leaflet to help parents and carers start conversations with their children about mental health.
In the pamphlet, Kate says: “As parents, we all want our children to have the best possible start in life.
“Encouraging children to understand and be open about their feelings can give them the skills to cope with the ups and downs that life will throw at them as they grow up.
“It’s important that our children understand that emotions are normal and that they have the confidence to ask for help if they are struggling.”
The Duchess’ video message is an introduction to an animated film, co-produced by children and teachers, which takes youngsters through different mental health scenarios and how they can cope if they have problems.
In the footage, Kate says about the animated film: “It helps us all talk about our mental health, what to say and who to talk to when we have feelings that are too big to manage on our own, and how to listen and help if one of our friends is finding things difficult.”
The Anna Freud centre is named after the pioneer of child psychoanalysis – and daughter of the famous psychoanalyst Sigmund Freud – who was instrumental in its creation.
She set up the Hampstead War Nurseries in 1941 in response to the social and emotional upheaval faced by children in wartime, and over the decades it developed into a centre of teaching and research and a major service provider.
The centre said research has shown half of all lifetime mental health problems start by the age of 14 and 20% of adolescents may experience a mental health problem in any given year.
Professor Peter Fonagy, the institution’s chief executive, said: “One of the most effective things we can do is to give children the language they need to discuss mental health and encourage them to have open conversations at home and at school.
“Helping children identify problems that they or their friends are having is the first step towards resolving those problems.
“If we can help children who are struggling with their feelings or experiences, they will be happier and perform better at school.”