The former first lady and the royal also attended the Obama Foundation Summit.
Prince Harry and Michelle Obama reunited for a good cause.
The 33-year-old royal and the former first lady surprised students at Hyde Park Academy, a high school in Chicago on Tuesday, ahead of the Obama Foundation Summit.
"Thanks to my friend Prince Harry for joining me today to surprise these remarkable students at Hyde Park Academy on the South Side. We were blown away by their passion, ambition and talent! #ReachHigher #ObamaSummit," Obama wrote on Instagram alongside a slideshow of her and Prince Harry with the students.
Hyde Park Academy is across from the "future site of the Obama Presidential Center on the South Side of Chicago."
"The warm and wide-ranging conversation, lasting over an hour, covered how the Obama Presidential Center will showcase the South Side of Chicago for a global audience, the importance of young people staying inspired and hopeful, and the transformative power of students using their voices to change the world," Kensington Palace wrote in a statement. "Prince Harry is on a short visit to Chicago where he will speak at the Obama Foundation Summit later."
According to the Palace, Prince Harry will talk about the Full Effect program and his work to provide platforms for young leaders.
The royal reunited with former president Barack Obama and former vice president Joe Biden last month at the Invictus Games in Toronto, Canada.
Also in attendance was Prince Harry's girlfriend, Meghan Markle. See how they spent their time together in the video below.