When Michelle Obama placed an arm around the Queen during a Buckingham Palace reception, it was regarded as a terrible faux pas.
Now the former First Lady has revealed the truth behind the apparent breach of protocol: the two women were commiserating with one another about their painful shoes, and the Queen was happy to have a hug.
In her new memoir, Becoming, Mrs Obama said the encounter ahead of the 2009 G20 summit began with the Queen looking up at her and remarking: “You’re so tall.”
Mrs Obama replied that her Jimmy Choo heels added a couple of inches, to which the Queen “gestured with some frustration at her own black pumps” and said: “These shoes are unpleasant, are they not?”
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She writes: “I confessed then to the Queen that my feet were hurting. She confessed that hers hurt, too. We looked at each other then with identical expressions, like, When is all this standing around with world leaders going to finally wrap up? And with this, she busted out with a fully charming laugh.
“Forget that she sometimes wore a diamond crown and that I’d flown to London on the presidential jet; we were just two tired ladies oppressed by our shoes.
“I then did what’s instinctive to me any time I feel connected to a new person, which is to express my feelings outwardly. I laid a hand affectionately across her shoulder.
“I couldn’t have known it in the moment, but I was committing what would be deemed an epic faux pas.”
The encounter sparked a flurry of negative headlines, and Mrs Obama said she worried that her behaviour had distracted from the diplomatic efforts of her husband, Barack.
But she insisted: “If I hadn’t done the proper thing at Buckingham Palace, I had at least done the human thing. I daresay that the Queen was okay with it, too, because when I touched her, she only pulled closer, resting a gloved hand lightly on the small of my back.”
Mrs Obama described the Queen as "an honest-to-goodness icon". She also recalled being awestruck by Buckingham Palace - "so big that it almost defies description" - and banquets at which they ate "with forks and knives coated in gold". She found the palace "breathtaking and incomprehensible at the same time".
Elsewhere in the book, Mrs Obama joked that the couple’s daughters, Malia and Sasha, became less impressed with their White House privileges as they entered their teens.
“Don’t you want to come downstairs tonight and hear Paul McCartney play?” they asked, as the former Beatle was about to perform a private concert.
“Mom, please. No,” came the reply.
Mrs Obama will promote her book with an appearance at London’s Southbank Centre on December 3. Tickets were in such demand that 80,000 people joined an online queue, and fans were outside the venue before dawn in the hope of securing a seat.
The Southbank Centre has said that any tickets sold by third parties will be cancelled, but that did not stop them being offered on secondary ticketing websites for up to £70,000.
Publication of the memoir came amid mounting speculation that Hillary Clinton could launch a bid for the US presidency in 2020, after a former adviser floated the idea of a remarkable political comeback.
Mark Penn, who worked with the Clintons for 13 years, and Andrew Stein, a former Democrat politician, wrote in the Wall Street Journal that “Hillary 4.0” would “come out swinging” and had learned from her painful 2016 defeat to Donald Trump.
Mrs Clinton sent mixed messages about a possible bid during a question and answer session last month.
Asked if she wanted to run for the White House again, she said, “No.”
But when the questioned noted there was a pause, Mrs Clinton added: “Well, I’d like to be president.”
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