She stepped onto the train platform alongside the princes Harry and William, as well as children from organizations affiliated with the Charities Forum, an umbrella organization of nonprofits the three royals all work with.
Royal watchers haven't seen much of Duchess Kate since September when she and Prince William announced that she's expecting their third child.
When the famous children's character asked Kate for a dance, the Duchess held out her hand and started twirling with the marmalade loving bear.
Kate's shoes, which are now sold out, looked gorgeous with her dress, which featured an embossed floral applique motif, dotted all over the design, and boasted a contrasting black-waist detail and a defined round-necked collar. Against all odds, a week after its grand re-emergence - his first official act since the announcement of her pregnancy - for the world Day of mental health in the secure Buckingham palace, Catherine joined her husband and her brother-in-law, a sign that she felt well enough for a meeting with the children benefiting from the assistance of several of the associations they support. (AAP) Actor Hugh Bonneville walks with the Duke and Duchess of Cambridge, Simon Farnaby and Prince Harry as they arrive at Paddington Station.
Kate, who wore an outfit by Orla Kiely, laughed her way through her dance routine with Paddington - to the amusement of William and Harry who were watching. The trio spent 45 minutes chatting with the children aboard the vintage Belmond British Pullman train before seeing them off, according to the Telegraph.
The event continued beyond the platform as the royal trio boarded the Belmond British Pullman train and joined more than 100 children representing numerous charities they support.
But the real star of the event was Paddington Bear himself, who appeared in all his furry splendor, complete with his trademark blue overcoat, on Monday.