Kate Middleton: Duchess has a fashion face-off with cross-dressing artist Grayson Perry

The Duchess of Cambridge had a fashion face-off with Turner Prize-winning artist Grayson Perry, as she visited a London primary school today.

Kate, who is six months pregnant, looked effortlessly stylish in a £450 loose-fitting navy dress by Madderson London.

Showing a hint of a baby bump, the naturally slim Duchess found she had competition in the style stakes when she arrived at Barlby Primary School in West London to meet Perry, who modelled a daring short black dress that he had designed himself.

The married father-of-one described the over-the-top black cocktail dress as his 'ladies who lunch' outfit.

"I thought it was appropriate for the occasion,' said the artist who seemed to have picked upon the trend for black tights inspired by Kate.

Commenting on the impact of the Duchess's presence he said: "If she goes somewhere the media will follow. It's up to her to use that to shine a laser beam upon the organisation with which she is working, it's her job. And she wields it with enormous grace as far as I can see."

The Turner prize-winning artist also described Kate as "looking pretty chic for six months."

The Duchess was at the school to officially name the new Clore art studio, which will be run by The Art Room, a charity which provides art therapy for underprivileged children. Duchess and Perry are both patrons.

Each week 85 children, all aged between five and 11, will receive art sessions designed to provide them with self-confidence, self-esteem and independence in the new studio.

Interacting with the children the Duchess took time to look at their works of art. When one little boy said to her: "You would like to be a chicken" she laughed and replied: "I would like to be a chicken? Maybe, actually!"

She also took part in a round table discussion with charity founder Julie Beattie and fellow patron Grayson Perry.

Head teacher Anthony Mannix said the Princess's visit was a boost to the children. "It is extremely exciting to be able to host HRH The Duchess of Cambridge as we can proudly introduce her to our children and show the school and our ethos.

"Since opening The Art Room in October, we have been overwhelmed with the positive benefits it has brought to the children."

The room is named after the Clore Duffield Foundation which has been making donations to The Art Room since 2005 and will cover the running costs for the new space over the next three years.

The Duchess had planned to officially open the facility last autumn but was forced to cancel the engagement after developing hyperemesis gravidarum, a severe form of morning sickness.

The Duchess left after an hour and was given a touching send-off by 250 flag-waving children - each of whom had drawn a portrait of the Duchess on the back of their flags.

The royal looked delighted and stopped to speak to several of the cheering youngsters before getting into her official car.

Kensington Palace said the engagement reflects the Duchess's interest in the arts and her commitment to supporting the concept of artistic creativity to enrich the lives of young people.