Samantha Cameron and Michelle Obama go head-to-head in fashion show down Who looked better? Miss Chapman, who had not known beforehand that Mrs Obama had selected one of her gowns, said: "I'm knocked out." Mr and Mrs Obama welcomed the couple to the White House at around 7pm, with the President remarking: "They look better than us." Roksanda Ilincic, who has dressed both Mrs. Obama and Mrs. Cameron, said: "First lady Mrs. Obama always looks so chic and modern. I love the addition of texture with the Tom Binns necklace. Dressing Mrs. Obama and Samantha Cameron have been wonderful. I am honoured that each woman representing their countries have been such advocates in their respective roles. Mr Cameron later joked about his well-documented visit to a basketball game with Mr Obama, saying: "We have to have a guys' night out because so often we find we are completely overshadowed by our beautiful wives." The sartorial efforts made by the two leaders and their wives was unlikely to go unnoticed at the event, which was attended by American Vogue editor Anna Wintour, who wore Chanel. British acting stars Carey Mulligan and Downton Abbey's Hugh Bonneville were also at the party as well as golfer Rory McIlroy. The evening's entertainment was suited to meet the President and Prime Minister's tastes with British folk rock band Mumford and Sons warming up for US R&B star John Legend. Other notable guests included The Wire star Idris Elba, Downton Abbey's Elizabeth McGovern, and movie mogul Harvey Weinstein. Virgin boss Sir Richard Branson, Olympic gold medallist Denise Lewis and politicians George Osborne and William Hague were also on the list. Mr Elba compared the evening to a visit to Disney World, where "you don't know what to expect next." Miss Lewis said she was as giddy as a schoolgirl, while Sir Richard said his wife was "very jealous" to miss the occasion. Paying tribute to the Prime Minister in a toast, Mr Obama said: "I've seen his character, I've seen his commitment to human dignity in Libya. I've seen his resolve, his determination to get the job done. And referring to the death of the Camerons' disabled son Ivan, who died in 2009 aged six, the president said: "I will say something else, David: all of us have seen how you as a parent along with Samantha have shown a measure of strength that few of us will ever know. Tonight I thank you for bringing that same strength and solidarity to our partnership. Mr Cameron responded by saying he felt the special relationship "in his bones." He praised Mr Obama's "strength, moral authority and wisdom," citing his decision to order the mission which led to the death of Osama bin Laden. "Let us all agree, the world is better off without bin Laden but the world is better off without Gaddafi too," said Mr Cameron. He said that Mr Obama had "pressed the reset button" on moral authority in the world.