The Duchess of Cambridge put her morning sickness behind her when Paddington Bear asked her for a dance – and she revealed she was fleet of foot.

Kate and the famous children’s character twirled and shimmied on platform one at London’s Paddington station, where Michael Bond’s creation was found all those years ago.

The impromptu ballroom dancing-style exhibition happened as Kate, the Duke of Cambridge and Prince Harry waved off a group of children from the station, as they embarked on a day trip in a vintage carriages pulled by a steam locomotive.

Kate, who is pregnant with her third child, is suffering from hyperemesis gravidarum – a severe form of morning sickness – but made a surprise appearance at the event, where the youngsters met some of the stars of the new Paddington II movie – including Hugh Bonneville.

The children taking part were selected by members of the royal trio’s Charities Forum – with many going through difficult times in their lives.

William, Kate and Harry boarded the British Pullman to talk to the youngsters before the train took them on a journey through the English countryside.

Later, as they waited to wave them off, Paddington Bear, complete with his famous duffle coat and hat, began dancing in front of them to music from a calypso band and, when he offered his hand to Kate, she took it.

The Duchess may have towered above the famous bear but they moved in time together and Paddington even twirled Kate around as the dance ended.

Still in character, the actor inside the bear, who declined to give their name, said: “She’s a right good mover, and I think she could win Strictly Come Dancing – if she was in it.”

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 royal trio had earlier boarded the train to chat to children nominated by their charities like Child Bereavement UK, East Anglia’s Children’s Hospice and the Diana Award.

Kate caused a flurry of excitement when she stopped to talk to Amelia Kubas, aged seven, and 10-year-old Mahira Gazi, both from Portway Primary School, in Stratford, east London.

The two schoolgirls told the Duchess they are helped by Place2Be, a mental health charity that provides in-school support for children and has Kate as its royal patron, with Mahira saying the encounter was “mind-blowing”.

She added: “I asked her what’s it like to be a princess, because I’d like to be one, and she said her favourite thing was meeting special people like us.”