The Duchess of Cambridge is to guest edit Huffington Post UK next month to help raise awareness of children's mental health.
She has campaigned against the stigma surrounding childhood mental illness, and is a patron of several related charities.
During her time at the publication, she will arrange contributions from a selection of leading figures in the area, Kensington Palace confirmed.
The Duchess will also hope to bring recognition to the work done by parents, teachers, researchers and mental health professionals across the UK.
A Kensington Palace spokesman said: "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."
Huffington Post UK editor-in-chief Stephen Hull said they were "thrilled" at the prospect of welcoming Kate in mid-February.
"We are thrilled that the Duchess of Cambridge is joining the HuffPost UK team for a day as a guest editor," he said.
"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."