The Duchess of Cambridge, who took several months off from public engagements following the birth of her third child, Prince Louis on April 23, looked very casual and prepared for an afternoon of exploring.
She stepped out in a green waterproof jacket, £475 Penelope Chilvers knee-high boots and khaki brown jeans thought to be by Zara, along with a green jumper and £395 white shirt with leaves on the collar by brand Joseph.
Continuing with the green theme, she was also wearing £125 Monica Vinader gold-plated wire earrings featuring green onyx.
The 36-year-old appears to have added sunkissed blonde highlights to her brunette locks, while onlookers said she was sporting a healthy tan.
Kate has travelled to Sayers Croft Forest School and Wildlife Garden at Paddington Recreation Ground in west London where she was greeted by school children who couldn't stop showering her with hugs.
After giving Kate a bunch of flowers, the adorable pupils shook her hand and gathered around her and cuddled her legs.
And when the Duchess asked the youngsters what their favourite thing about the wildlife school was, they told her: "Eating" leaving Kate in giggles.
Kate also took part in a 'mini beast' hunt searching for bugs with one pupil and planted pea seeds with another, before going on a forest walk.
She was also seen helping the children fill up their watering cans and making leaf crowns.
One cheeky pupil also left Kate chuckling as the youngster messed around with a cup while sat beside the royal during storytime.