Beyoncé Knowles visited two fans in hospital who were injured when a fireworks display went wrong at her concert.The 'Crazy In Love' singer was performing at America's St. Louis' Scottrade Center on Sunday night when fireworks meant for the stage landed in the front row, causing two concert goers to suffer minor injuries. After the show, Beyoncé, 25, visited the Emergency Room at Barnes-Jewish Hospital to check how they were. Head nurse Darryl Williams told People magazine: "She was just very concerned about the people injured in the audience."It was unannounced and we kept it very low-key so that she could spend time with them. I just thought it was a great thing for someone of her stature to do."The 'Dreamgirls' star spent 45 minutes with the two fans who are expected to make full recoveries. Beyoncé is currently on her world tour which began in Tokyo, Japan, in April. It finishes in Vancouver, Canada, in early September.This week Beyoncé performs in Mexico and Texas.