WATCH: Kate Middleton's plea to parents

Kate Middleton is the star of a new public-health campaign in the UK, with the Duchess recording a video of herself speaking out to parents about caring for children's mental health.

In her first appearance since the announcement of her third pregnancy, Kate wore a $2700 blue coat by London-based label Eponine as she implored her fellow parents to be mindful of everyone in the family's mental wellbeing.

"As parents, we all want our children to have the best possible start in life," Kate said.

"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."

RELATED: Did Kate Middleton just give away the sex of her baby?
RELATED: Kate Middleton wants a home birth

She went on to describe the importance of ensuring kids feel comfortable asking for help if they need it.

"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," Kate said.

"This is why I am proud to support the 'You're never too young to talk mental health' campaign by the Anna Freud National Centre for Children and Families, which is being rolled out across primary schools this autumn.

"The campaign's resources are excellent tools to support parents. They demonstrate how we can help children express their feelings, respond appropriately, and prevent small problems from snowballing into bigger ones."

The video was shot in January, when Kate paid a visit to the Anna Freud National Centre for Children and Families.

Want more celebrity, entertainment and lifestyle news? Follow Be on Facebook, Twitter, Pinterest, Tumblr and Instagram