The BBC's annual telethon was taking place on Friday night, and Kate said she was "delighted" to be invited to open the show.
"Tonight is all about helping to support, champion and empower all children to be the very best they can be, which is crucial for their future health and happiness," she said in her televised opening address.
"Our relationships, surroundings and experiences during the earliest years lay the foundations that shape the rest of our lives.
"And yet sadly, we know that for too many people, stressful and traumatic situations in early childhood can cause harm and it can take many years to overcome.
"It is vital, therefore, that we nurture every childhood and why the sorts of projects supported by Children in Need are so important.
Delighted to support this year’s #ChildrenInNeed 💛
We must nurture every childhood, which is why the projects supported by @BBCCiN are so important.
Thank you to everyone around the country taking part in challenges and the amazing fundraising effort 👏 pic.twitter.com/z7oOTbtHMJ
— The Prince and Princess of Wales (@KensingtonRoyal) November 17, 2023
"They help the very youngest, most vulnerable members of our society feel safe, secure and loved in these important, formative years, so that they can enjoy their childhoods now, and grow to reach their potential and thrive in the world in later life.
"I hope you enjoy this evening’s show and best of luck to all those taking part in challenges and the incredible fundraising effort."
In January this year, Kate launched her “life’s work”, an ambitious campaign called Shaping Us, aimed at raising the profile of the early years development of children and highlight the significance of the formative years of a child’s life.
Since its launch in 1980, Children in Need has raised more than £1 billion for disadvantaged children and young people in the UK.
The Children in Need Appeal Night Show was due to air on BBC1 and iPlayer from 7pm to 10pm on Friday, featuring a host of new shows and sketches.
The BBC promised "a jam-packed evening of sketches and performances featuring well-known faces as you've never seen them before.”
A one-off scene from Doctor Who was set to introduce the 14th doctor, David Tennant, while in the Masterchef kitchen John Torode and Gregg Wallace were set to be joined by some of Britain's best-loved puppets, all competing to cook and create a dish to win over the judges.
New sketch Race Across Yorkshire, a parody of the show Race Across the World, was also set to air as part of Children in Need coverage. It was set to feature appearances from Yorkshire icons, and pitstops to earn cash along the way.Fans are asked to tune in on the night and donate what they can to the cause, with funds going to local charities and projects across the UK to remove the barriers facing children and young people.
More than 2,500 local charities and projects throughout the UK receive funding from Children in Need.