Last night, the former US first lady upped the fashion stakes by wearing a custom, black beaded jumpsuit by British fashion designer McCartney.
Mrs Obama accessorised with large gold hoops by Jennifer Fisher jewellery, and finished off her look with a pair of classic, black Jimmy Choo heels.
Throughout the international tour for her best-selling memoir, the former US first lady has made a point of championing designers from different countries.
While in Copenhagen last week, Mrs Obama wore a bespoke hand-embellished pink power suit by Danish designer Stine Goya.
The former first lady's ensemble for the London leg of her book tour was put together by her long-time stylist Meredith Koop.
Ms Koop has spoken in the past about the importance of perfecting every element of Mrs Obama's looks, in order to anticipate whether or not they may receive a positive or negative reaction.
“You have to celebrate fashion but also be aware of the message people are going to take away,” Ms Koop told the New York Times in 2018.
“Fashion can bolster communications in the best-case scenario, or be a silent partner, or actually distract.”
During the evening, the author spoke to the audience about being "more sceptical about social media and the Internet".
“Don’t read about your neighbours on Twitter. Somebody can talk into your ear about the person living next to you – and they can feed you lies and misperceptions," the 55-year-old said.
“Put down the phone and start knocking on doors. People can never be as mean to you to your face as they would be online.”
The former first lady also detailed her first impression of Barack Obama when she met him at law firm Sidley and Austin in Chicago in 1989.
“He was the talk of the firm; this kid who wasn’t even a lawyer – who hadn’t finished law school and was a first-year associate," she stated.
"He was coming in already with this sort of sense of wonderfulness.”
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