Beyonce surprises students at PS/MS 161 in Harlem as part of First Lady Michelle Obama's "Let's Move" initiative to fight childhood obesity.

Beyonce surprises students at PS/MS 161 in Harlem as part of First Lady Michelle Obama's "Let's Move" initiative to fight childhood obesity. The students were dancing to "Move Your Body," which the singer recorded for the initiative. Middle School students from around the country were participating in the four-minute flash dance routine simultaneously 1:42 pm EST on May 3, 2011 in New York City.