Kate looked stunning in a floor-length beaded blue gown that perfectly matched her sapphire engagement ring.
While at the event, the 38-year-old mother of three, who is a royal patron of the organization, greeted school children and posed for photos with them. She also spoke at the gala and the children performed a musical number.
"Place2Be was one of the first charities I became patron of. I knew it was special then, but having spent many years since, learning about the importance of childhood development, I see even more the value in the work that you do and I am hugely grateful for all that you have taught me over the past seven years," Kate said in her speech. "You taught me, right from the start, that the children in your schools are only as happy and emotionally strong as the adults in their care."
It's been a colorful first day of the week for Kate! For the Commonwealth Day service on Monday morning, the duchess stepped out in a dark red coat dress that she paired with a fascinator, heels and a clutch of the same color.