The Duchess of Cambridge has urged society to view children's mental health as being "every bit as important as their physical health" as she began her guest editorship of the Huffington Post UK.
Writing a blog to mark her role at the helm of the news site, she spoke about the psychological well-being of her own children Prince George and Princess Charlotte, saying she and William "would not hesitate to seek help for our children if they needed it".
Kate sat down to a morning conference in Kensington Palace with Huffington Post UK editor Stephen Hull, his staff and some of the mental health charities she is associated with.
She has commissioned articles, blogs and videos from leading figures in the mental health sector to raise awareness about the psychological well-being of the nation's children.
The Duchess wrote: "The mental health of our children must be seen as every bit as important as their physical health.
"For too long we have been embarrassed to admit when our children need emotional or psychiatric help, worried that the stigma associated with these problems would be detrimental to their futures."
The Duchess went on to say: "We hope to encourage George and Charlotte to speak about their feelings, and to give them the tools and sensitivity to be supportive peers to their friends as they get older.
"We know there is no shame in a young child struggling with their emotions or suffering from a mental illness."
From a newsroom set up in a palace drawing room, Kate used a computer mouse to launch the news website's top story or "splash" - a piece titled Never Too Young, about the importance of early intervention for those with mental health problems.
James Martin, a Huffington Post executive editor, asked the Duchess if she wanted to click the button to send the story live and told her: "This is the current splash which we have on the site which is your fantastic blog."
He added: "We've prepared what we call a splash, which is a hangover term from the time of newspapers when you'd splash a story on a newspaper and it's translated here into digital."
As she clicked the button Kate, who wore a Dolce and Gabbana skirt and shirt by Reiss, smiled and laughed.
The Duchess told all those in the room: "Can I just say a huge thank you to Stephen and obviously the huge team that's been involved in this, turning it around so quickly."
Mr Hull made the group laugh when he joked: "You've been a good boss."