White House Royalty: Michelle Obama at UK State Dinner

In order: Samantha Cameron, First Lady Michelle Obama, British Prime Minister David Cameron, and U.S. President Barack Obama pose for photographs on the North Portico of the White House before attending a sate dinner March 14, 2012 in Washington, DC.

The frock is designed by New York-based label Marchesa, whose co-founder is Georgina Chapman, the British-born wife of Hollywood producer Harvey Weinstein — and a guest at Wednesday’s dinner.

Meanwhile, Samantha Cameron is wearing a dress by British designer Alessandra Rich.