The president may be making his debut on the global stage -- but its the first lady who is stealing the show.
Michelle Obama won over Brits with her easy elegance and sunny demeanor as the European press breathlessly follows the first lady's every move -- from her fashion choices to her hair style to the deep relationships she's developed with the country's leaders.
The Brits are "completely in love" with Michelle, editor of Vogue London Alexandra Schulman told ABC News. "I think she could do no wrong."
Michelle has been likened to the stylish and beloved former first lady Jackie Kennedy and some have claimed she is the new Diana -- others even go as far as to use her sparkling wardrobe as a metaphor for the change the G-20 summit will be able to effect.
"The excitement British women feel about the arrival of Michelle Obama in London for the G-20 summit is spiked with awe," Tina Brown wrote in the Daily Beast. "She's so big-time. So self-confident. So devoid of rainy, British diffidence."
Fashion is just one part of the Michelle mania that has gripped the country but it is a large part of the first lady's appeal.
Dubbed one of the "fluffies" -- First Ladies who Understand Fashion" -- by a British paper, Michelle was praised for the black-and-white coast and shift by Thakoon that she wore on Air Force One and the cream J Crew cardigan she wore during the day Wednesday sold out of stores, J. Crew told ABC.
So far, the first lady has donned designs by Isabel Toldedo, who designed her inaugural dress, and Jason Wu, who designed her inaugural ball down.
But perhaps the most awe-inspiring moment for the Brits was Michelle's historic meeting with the Queen yesterday.
It was "absolutely extraordinary" as the Queen put her gloved hand on the small of the first lady's back and Michelle put her arm around Her Majesty's shoulders during a meeting at Buckingham Palace yesterday, the Daily Mail reported.
Never in 57 years had the Queen made such a gesture, which is a clear violation of protocol, the paper reported.
"But she didn't seem to mind a bit and was smiling and joking throughout," a witness said.