Michelle Obama channels inauguration glamour at Buckingham Palace banquet in showstopping white Tom Ford gown

She's not set a foot wrong on her visit to the UK so far, demonstrating support for both American and British labels. But tonight's State Dinner at Buckingham Palace saw Michelle Obama step out in her most stunning look yet.

The long white evening gown, by Tom Ford, showed off her famously toned arms to great effect - not unlike the white Jason Wu creation she wore to one of her husband's inaugural balls in January 2009.

The straps, which crossed high at the neck, were demure enough to hide her décolleté while exposing the shoulders, and the wide sash, positioned just beneath the bust, nipped her waist at its narrowest part.

First Lady of flawless: Michelle Obama in a white Tom Ford gown for tonight's State Dinner with the Queen at Buckingham Palace (left) and in Jason Wu in January 2009 at one of her husband's inaugural balls

The elegant look, which was completed by long white evening gloves and the tiniest jewelled clutch purse.

It bore many of the hallmarks of her now-famous Jason Wu gown - the garment that arguably put her on the fashion map. Her endorsement of the young designer (Wu is now only 28) had a huge effect on his career and his designs are now sold all over the world.

The Queen also wore white, as is tradition for a State occasion. Her Stewart Parvin silk crepe evening gown had an embroidered Swarovski floral motif bodice. She wore it with the Vladimir diamond and pearl tiara.

Formal occasion: The Queen wore Swarovski-embellished Stewart Parvin with the Vladimir tiara, while President Barack Obama and the Duke of Edinburgh were both dressed in traditional white tie

Around 170 guests including U.S. Secretary of State Hillary Clinton, Prime Minister David Cameron and his wife Samantha attended the white tie dinner in the grand Buckingham Palace ballroom.

Actors Tom Hanks and Kevin Spacey, actress Helena Bonham-Carter and her director husband Tim Burton added some Hollywood glitz to the lavish event.

Former Prime Ministers Sir John Major, Gordon Brown and Tony Blair with wife Cherie were also invited, but the newlywed Duke and Duchess of Cambridge, who earlier met the Obamas, were not there.

In her address, the Queen hailed the U.S. as Britain's 'most important ally', renewing the bonds of friendship with President Barack Obama at the banquet in his honour.

The three day stay comes at a time of close co-operation between Britain and the US on Libya, Afghanistan, counter-terrorism and the Middle East peace process.