A citywide flash mob is a tough feat. Keeping 21,000 dancers along Michigan Avenue a secret from Oprah is even tougher. But choreographer Michael Gracey and the Oprah Show
producers pulled out all the stops for the massive surprise that kicked of Oprah's 24th season
. Oprah says the dance, set to an "Oprah Feelin'" mix of the Black Eyed Peas' "I Gotta Feeling," was one of the best surprises of her career. Watch how we made it happen
, then learn the dance for yourself.