While performing "Single Ladies", she stopped for a surprise for her lead dancer, Ashley Everett.
http://www.youtube.com/watch?v=iOcLa9P3aG4 Single Lady no more! Dance Captain to Lemonade singer Beyoncé, Ashley Everett, gets a special surprise at the St. Louis stop on the Formation World Tour. Boyfriend, fellow dancer / choreographer and St. Louis native, John Silver, interrupted Queen Bey and the Beyhive during a performance of “Single Ladies” to publicly express his love and appreciation […]
Led by Bey's head dancer, Ashley Everett, the ladies went through their "Formation'' choreography.