London (CNN) Michelle Obama has revealed Queen Elizabeth II's surprising view on royal protocol at a speaking engagement in London on Monday.

The former US first lady recalled worrying as she prepared to be picked up by the British monarch in her car during a visit to Windsor Castle in 2016, reports the UK's Press Association.

"So I had all this protocol buzzing in my head, and I was like 'don't trip down the stairs and don't touch anybody, whatever you do,'" Obama said. "And so the Queen says 'just get in, sit wherever' and she's telling you one thing and you're remembering protocol and she says 'Oh it's all rubbish, just get in.'"

Obama also revealed husband and former US President Barack Obama is a big admirer of the Queen because she reminds him of his grandmother Toot.

"She's smart and funny and honest," she said. "He is a huge fan for sure."

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