Washington (CNN) Former first lady Michelle Obama said she initially doubted America was "ready" for a black president during former President Barack Obama's 2008 campaign.

"One of the reasons why I agreed to support Barack's run for president was that deep down I was like, 'there's no way he's going to win.' And we can just sort of get this out of the way, and I can be that supportive wife going 'oh, honey, you tried. Um, OK, now let's go back to our lives as usual,'" Obama said Monday in London at an event to promote her new memoir "Becoming."

"That was my whole plan, you know, because I didn't believe that America was ready for a black president, let alone a black president named Barack Hussein Obama," she said.

At the event, hosted by author Chimamanda Ngozi Adichie, Obama also said it was foolish to believe that her husband's ascendancy to the presidency meant the end of racism in America.

"My grandparents' lives were affected by Jim Crow. We mistakenly thought that Barack Obama was going to erase hundreds of years of history in eight years. That is ridiculous," she told attendees.

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