Michelle O: Gorgeous gowns and dazzling bling!

US President Barack Obama and his wife Michelle Obama hosted a dinner for Britain's Queen Elizabeth II at Winfield House - the residence of the Ambassador of the United States of America - in Regent's Park.The First Lady of the United States, Michelle Obama, looked effortlessly stylish as the Obamas spent two days in London, as part of a six-day Europe trip.

The First Lady scored a fashion win in a stunning black off-the-shoulder dress by American designer Ralph Lauren at the black-tie dinner. Michelle Obama also showed off a selection of jewels, including a Tom Binns cuff and necklace.

The sleek updo added to Michelle Obama's stunning appearance.

The First Lady set herself ahead of the fashion pack one more time with this appearance.

Mrs Obama sparkled at the dinner where the dress code was black tie.

Michelle Obama dazzled in the diamond necklace and matching bracelet.

The First Couple share a moment as they wait for their royal guests.

Guests, who numbered more than 50, included Hollywood actor Tom Hanks and Oscar winner Colin Firth.

The Royals and the Obamas at Winfield House.

The US President holds open the guest book for Queen Elizabeth II to sign as Michelle Obama and Prince Philip look on after the dinner at Winfield House.

The Queen wore an Angela Kelly white evening dress with gold and silver sequins and an emerald necklace and matching earrings.

Mrs Obama kept her look elegant in a knee-length shift dress during the Obamas' daylong visit to Ireland.

The First Lady arrived in the UK dripping elegant style in royal blue outfit by Preen.

At the Buckingham Palace state banquet hosted by Queen Elizabeth II, Michelle Obama looked elegant in an off-white crisscross gown by Tom Ford with matching gloves, metallic clutch and updo.

Some style watchers say the First Lady failed to score a perfect 10 when she met another fashion plate – the new Duchess of Cambridge, Kate Middleton, at Bucks Palace. Michelle Obama wore a pale green, floral, a-line dress from American designer Barbara Tfank's 2011 resort collection.

The Duchess of Cambridge scored a win with a beige, short-sleeved, Shola "bandage" dress from Reiss, one her favorite designers.

Mrs. O's resort look made way for a magenta Roksanda Ilincic dress with a cobalt blue Narciso Rodriguez coat.

Mrs O chose a crystal embellished black chiffon dress by American designer Tracy Reese as she prepared to serve food with Samantha Cameron, wife of Prime Minister David Cameron, at a barbecue for British and American service members and veterans. Sam Cam opted for an outfit by British designer Jonathan Saunders.

During her address to the students from the Elizabeth Garrett Anderson School at Oxford University, Mrs O gave British fashion a boost by opting for one of the best-known British labels, Alexander McQueen. She picked a white cotton tunic shirt and large Western style belt from the summer collection.