Kate Middleton has pledged that her early years campaign will provide parents with the "very best information and support" needed to raise their children.
At an event staged on the eve of the project's launch, the Princess of Wales spoke about the "critical importance" of the first five years of a child's life and its influence on their future.
The princess's Shaping Us campaign aims to improve society's understanding of the significance of early childhood in shaping adulthood and society as a whole.
The initiative will be launched on Tuesday by the Royal Foundation Centre for Early Childhood, and the princess hopes it will influence attitudes toward children in the early years of their lives.
Kate was joined by husband William and a host of celebrity supporters at the evening event staged at Bafta's London HQ, with former Saturdays singer Rochelle Humes, rapper Professor Green, presenter Fearne Cotton and England football captain Leah Williamson among the guests.
In a speech, the princess said: "The campaign is fundamentally about shining a spotlight on the critical importance of early childhood and how it shapes the adults we become.
"During this time we lay the foundations and building blocks for life.
"And it is when we learn to understand ourselves, understand others and understand the world in which we live.
"This is why it is essential, to not only understand the unique importance of our earliest years, but to know what we can all do to help raise future generations of happy, healthy adults."
Kate outlined the scope of the campaign, describing it as a long-term project beginning with how a child develops and the importance of the formative years.
It will go on to "explore in more depth the importance of a child's social and emotional world" and the significance of relationships and "surroundings and experiences".
She added: "And of course, by understanding our own childhoods - what has shaped our own beliefs, relationships, behaviours and feelings - we, as adults, are better placed to play our part in positively shaping future generations."
In an open letter released on Saturday evening, she urged people to think about how they make the world a "more supportive and loving place" for children.
Kate wrote: "During our very early childhood, our brains develop at an amazing rate - faster than any other time of our lives. Our experiences, relationships, and surroundings at that young age, shape the rest of our lives.
"It is a time where we lay the foundations and building blocks for life. It is when we learn to understand ourselves, understand others and understand the world in which we live.
"But as a society, we currently spend much more of our time and energy on later life.
"I am absolutely determined that this long-term campaign is going to change that.
"It will start by highlighting how we develop during early childhood and why these years matter so much in terms of shaping who we become."
Kate said the campaign has the support of science and research experts, as well as notable faces from music, sport and television.
It is hoped they will help find ways to give generations of children the best start in life.
She added: "We all need to know the critical importance of our early childhood. They really are years like no other in our lives.
"I urge everyone reading this, to take the opportunity to learn more about this incredible time of life, to think back to your own childhood and how it shaped you, and most importantly, to ask yourselves what you can do to make the world a more supportive and loving place for our children.
"Because healthy, happy children shape a healthy, happy future."
Neil Leitch, chief executive of the Early Years Alliance, said: "The Princess of Wales is absolutely right to highlight the need for greater recognition of the importance of the early years.
"There is a wealth of research that shows that the first five years of a child's life are critical to their long-term learning and development, and yet all too often in this country, education policy - and funding - is focused on the school years and beyond, while our vital early education sector remains overlooked and undervalued.
"We are hugely grateful to the Princess of Wales for using her platform to raise awareness of the need for action on this important issue - and hope that policymakers might just finally sit up and listen."
