Kelly Clarkson led a harmonious flash mob in Central Park before her Vegas residency. The group sang her song "Lighthouse" from her latest album Chemistry. Kelly wore a long dress as she belted out the song. Despite winning American Idol in 2002, Kelly's career has continued to thrive with multiple albums and awards. She is also a successful talk show host. Kelly surprised fans in LA with two flash mobs before her Vegas residency. Her album Chemistry, released after her divorce, delves into her emotions.