The 33-year-old took Prince George to the Natural History Museum on 22 October, where, despite the Diplodocus dinosaur skeleton being present, the little royal cast his attention to the pigeons outside.
Kate glowed in a grey Orla Kiely dress at the Chance UK charity event in Islington
Kate told of her son's fascination with insects, especially his love for ladybirds, when she met young people from the charity Chance UK, which mentors vulnerable children in London who are at risk of offending.
It operates an early intervention program, aiming to change challenging behaviour of primary school-aged children through intensive and individual mentoring, as well as family support.
The Duchess wore a grey dress by Orla Kiely for Tuesday's event with the charity at Islington Town Hall in north London.
The Duchess met with children involved in the charity's early intervention program
Kate met with Carl Goddard, 10, from Haringey, north London, and his mentor Claire Butler, 29.
Carl showed Kate a picture of him at the Natural History Museum with a fox. "She was telling me that she took George to the Natural History Museum," he said.
Claire added: "She said that George was more interested in a pigeon they found there rather than all the amazing exhibits."
Prince George marks his first birthday at a trip to the National History Museum
Kate also met with Faith Buchanan, 8, and her mentor Elizabeth Little, 33. Faith said, "We were talking about insects and she said George likes them."
"She said George's favourite was the ladybird," Elizabeth added. "It was amazing to meet her, Faith did all the talking, she was great and (Kate) was really interested in the charity.
Rimi Rahman, one member of the public who saw the royal visitors at the museum, told People: "She was holding George's hand, showing him around and talking to one of the people who worked there. People didn't really notice her at all. They went all around the dinosaur gallery – George looked so cute and little, his hair is so nice. He looked so happy."
Prince William, Prince George and Kate Middleton at the Natural History Museum in 2014
The museum confirmed that Kate, their royal patron, had paid a visit with her son George.
It is not the first time the young Prince has paid a visit to the museum; George also enjoyed a day out there before he turned one, with the museum's butterfly exhibition serving as the setting for his official first birthday photos.