The Duchess of Cambridge has urged parents, teachers and healthcare workers to give child mental health the "focus it requires".
In a message to the Times, Kate welcomed steps to end the taboo around adult mental illness and reiterated the importance of early intervention.
The Duchess, who is due to give birth to her second child next month, has spoken out on the subject before in her role as a patron of charity Place2Be.
She told the newspaper: "I have been heartened to see that so much progress has been made in ending the taboo of adults openly treating mental well-being as the health issue it is.
"I believe that our generation of parents, carers, teachers and health workers now have the chance to give the mental health of our children the focus it requires.
"I feel strongly that young people and parents need to know that they can ask for help. Just as with physical health, we need to act early to provide support when a child needs it."
Kate also said she and husband William hoped to "play a part" in the public discussion around mental health in the future.
The comments come after the Government announced more than £1.25 billion will be spent on mental health services for children and new mothers in last week's Budget.
The bulk of this will go on improving access to mental health services for youngsters, which will see more than 110,000 more children cared for over the next five years.
Kate became patron of Place2Be - the leading UK provider of school-based mental health support - in 2013 and is passionate about its cause. She has become closely involved with its attempts to provide early intervention for children before problems escalate.
In an video message last month, she said: "Through Place2Be I have seen the benefits of offering children support for their mental health in the safety of the school environment.
"Both William and I sincerely believe that early action can prevent problems in childhood from turning into larger ones later in life."