The warming "special relationship" between the US and UK has continued to focus on the fashion sense of the first ladies.

It was a high-fashion event at the state dinner where US President Barack Obama and Michelle Obama welcomed Prime Minister David Cameron and his wife, Samantha.

The prime attraction was not affairs of the state but the state of the fashion when the first ladies arrived in colour-coordinated designer gowns.

Samantha Cameron donned a blue lace dress by London-based Italian designer Alessandra Rich having three-quartered sleeve and a belted waist. She paired her dress with black heels from British retailer Next.

Michelle Obama opted for an off-the-shoulder teal silk dress from American fashion house Marchesa. The gown was designed by British designer Georgina Chapman. She complemented her blue gown with a bold blue statement necklace by Tom Binns.

Other guests present at the event included Vogue editor-in-chief Anna Wintour, designer Roksanda Ilincic, Harvey Weinstein and Georgina Chapman, all looking out for fashion tips.

The state dinner was staged at the end of the first day of the Cameron's three-day visit to the US.