The Duchess of Cambridge, 34, will be the guest editor of Huffington Post UK and has invited a team from the online news service to her Kensington Palace home here in mid-February.
She will use the guest role to highlight work being done by teachers, parents, researchers and mental health professionals.
"The Duchess of Cambridge has made the mental health of young children a key focus of her work in recent years. She is delighted that The Huffington Post will help put a spotlight on this important issue," Kensington Palace said in a release.
Stephen Hull, editor-in-chief of Huffington Post UK, said: "We are thrilled that the Duchess of Cambridge is joining the HuffPost UK team for a day as a guest editor.
"Dealing with mental health issues has been a major editorial focus for us and I'm very excited to be working together on such an important project."
One of the charities of which the royal has become a patron since marrying Prince William in 2011 is Place2Be, which provides school-based mental health and emotional support services, helping over 67,000 children in 175 schools across Britain.