Michelle Obama surprises students at Detroit's Motown Museum during Becoming tour

Michelle Obama surprised a group of Detroit college students on Tuesday afternoon when she walked into the Motown Museum. The young students were taking part in a roundtable discussion on education.

The former first lady was greeted with smiles, looks of astonishment and applause after entering the second floor of the building where Berry Gordy created sonic history more than half a century ago.

She hugged her brother Craig Robinson and Keegan-Michael Key, an actor and native Detroiterwho moderated the discussion that was organized by Obama's Reach Higher initiative.

"This was supposed to be for boys only," said Robinson, after they sat down, eliciting laughter from his sister and the more than a dozen students from nearby Wayne State University.

"What's going on," Obama then asked, echoing the title of Marvin Gaye's classic Motown tune.

"We're just talking about education," Key answered, before mock-asking if it would be OK with the students for Obama to sit in on their chat.

She listened as the students spoke about their experiences in life and school, encouraging them to practice "discomfort" and not be afraid to try new things.

"Universities are looking for and should be looking for a diverse array of experiences," she said.

"People who come from different backgrounds, because if everybody looked the same and experienced life the same way, what would these conversations be like? Just a bunch of people agreeing with each other."

Obama is in Detroit as part of her book tour, which features a night-time stop at Little Caesars Arena. The tour is in support of her best-selling memoir, Becoming.

She will be headed to Denver, Colo. after the Detroit stop. Her first stop in Canada will be in Vancouver in March.