Speaking about the bond between the former President and the royals, Obama also revealed how the Queen reminds her husband of his grandmother.
Former first lady Michelle Obama took the stage Saturday night at the Barclays Center in Brooklyn, where she was interviewed by the poet Elizabeth Alexander in front of a packed arena. '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". 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"'.
Mrs Obama added that her husband had always had a great affection for the Queen, saying: "Barack is so incredibly fond of Her Majesty and I won't go into his fangirling but I think it's because she does remind him of his grandmother Toot, she's smart and amusing and honest".
When getting in a vehicle together, Her Majesty apparently also said: "Just get in, sit wherever".
CNN has reached out to Buckingham Palace for comment.
The lawyer and wife of former president Barack Obama will speak to a London audience about her memoir Becoming.
"Like me, Meghan probably never dreamt that she'd have a life like this, and the pressure you feel - from yourself and from others - can sometimes feel like a lot", she told Good Housekeeping magazine.
"This was on our last visit and we went to Windsor Castle and we took Marine One, the helicopter, and we landed in a field and we were going to be driven by the Queen and picked up in the auto".
The pair also discussed the current political situation in the United States and the idea of progress in civil rights.
Michelle Obama visits the Lower Eastside Girls Club in New York City on December 1 to discuss her new book, Becoming.
"We are putting down markers, we make progress and going backward doesn't mean the progress wasn't real".
"I was 16 at the time (of her first visit) and I think just as a role model to look up to as a strong, beautiful, empowered woman, her emphasis on education, feeding back through to the younger generation (is important)".
"We are angry, we are too loud, we are too everything and I experienced that, just campaigning, just speaking truth to power, how dare I have a voice and use it?" she said.
Michelle Obama's memoir has become the best-selling book of the year in the USA, surpassing Michael Wolff's "Fire and Fury" and others. "I thought we were at home, y'all", she said.
Letrishka Anthony was 16 when Mrs Obama first visited Elizabeth Garrett Anderson School during her first year in the White House and is one of the school's alumni to join her on a visit to the campus nine years later.