Latest Update: Kate’s mate! Princess walks hand-in-hand with Grace, 5, after getting bus with school children….See More

The Princess of Wales looked delighted today as she arrived at the National Portrait Gallery in central London hand-in-hand with a five-year-old girl after riding next to her on the bus.

Kate, 43, launched an ‘interactive trail’ to support social and emotional development in under fives with pupils from All Souls CE Primary School in Marylebone.

The Princess rode the bus with pupils and made a special bond with five-year-old Grace, walking hand-in-hand with her throughout the gallery – despite the young girl having no idea who the royal was.

Kate was dressed in in a brown blazer over a black high-necked wool jumper, as well as £220 pinstripe Jigsaw trousers.

Adding to the glamorous look, Kate wore her Sézane Bruna Earrings and her Halcyon Days Salamander Torque Forget-Me-Not & Gold Bangle – believed to be a gift from Prince William.

While Her Royal Highness bonded and chatted to dozen of pupils, Grace, five, became firm friends with the Princess, clutching her hand as they arrived after they sat together on the bus.

Alix Ascough, executive headteacher at All Souls, said: ‘Kate had been asked if she would have a partner, and she was sat next to Grace on the coach and Grace had chatted away to her the whole journey.’

But the youngster did not know she was holding hands with the future Queen.