"We know that mental health is an issue for us all - children and parents, young and old, men and women - of all backgrounds and of all circumstances", Kate told pupils and staff at Roe Green Junior School (via People).
The Duchess of Cambridge is launching a new website to help children access better mental health support in school.
The "Mentally Healthy Schools" website draws together reliable mental health content gleaned from more than 1,500 online resources, which were reviewed and evaluated by a quality assurance group to ensure the suitability for a primary school audience.
One in 10 children experience a mental health difficulty by age 11 and until now, many teachers looking for advice on the issue have found the information available hard to navigate, as it is often unclear whether it is expertly verified.
The news comes as it was revealed that the duchess may be planning a home birth for her third child.
But don't panic - whoever she left the ring with kept it safe, as it was seen safely back on her left hand today when she visited youngsters at Roe Green Junior School to launch a programme that supports children's mental health at school.More news: 2018 survey to count the homeless in Columbus; provide them with resources
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When Kate first arrived, she joined a staff room meeting where teachers and other guests were discussing the issue of mental health in schools, and the duchess asked the question: "Do you think teachers are wanting to improve the mental health of their pupils but they're not able to get the right resources?"
A blue skirt could be seen peeping out from underneath the Duchess' coat when she bent down to speak to children at the school.
"So, no matter what their role in the school, they need to have an understanding and empathy towards all the children".
AFP/Getty Images Town crier Tony Appleton announces the birth of Princess Charlotte outside the Lindo wing at St. Mary's Hospital on May 2, 2015.
"When we intervene early in life, we help avoid problems that are much more challenging to address in adulthood".