It was the moment that spawned a million protocol experts. When Queen Elizabeth II met then US First Lady Michelle Obama in 2009, the two women hugged and nobody could stop talking about it.

Michelle Obama was accompanying her husband, US President Barack Obama, to the G20 Summit when she met Queen Elizabeth II for the first time.

In her memoir, Becoming, Michelle Obama describes the moment as one of small talk: they’d been commiserating about how uncomfortable their shoes were—both in heels.

“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,” Michelle Obama wrote.

Then, the moment came where Mrs Obama wrapped her arm around Queen Elizabeth II’s shoulders in an apparent breach of royal protocol—though no such rule exists. Queen Elizabeth II mirrored the First Lady, wrapping her own arm around her waist.

“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,” Michelle Obama wrote. “I couldn’t have known it in the moment, but I was committing what would be deemed an epic faux pas.”

The long-held (and often wrong) rules pertaining to royal protocol have been deemed to include the edict that no person can touch The Monarch. However, Angela Kelly, Personal Assistant, Adviser and Curator to Her Late Majesty, wrote in her book The Other Side of the Coin: The Queen, the Dresser and the Wardrobe otherwise.

“Much has been made about the meeting between Michelle and Her Majesty when an instant and mutual warmth was shared between these two remarkable women, and protocol was abandoned as they stood closely with their arms around each other’s backs. In reality it was a natural instinct for the Queen to show affection and respect for another great woman and really there is no protocol that must be adhered to.”

Mrs Obama added: “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.”

Michelle Obama would say on the press tour that she had no regrets about what had happened, and expressed admiration for Queen Elizabeth II.

Her Late Majesty is reported to have enjoyed a good relationship with the Obamas as well.