NEW ORLEANS - Beyonce vowed to sing live at her Super Bowl half-time show, confirming she sang along to a pre-recorded recording of the US national anthem at President Barack Obama’s inauguration. The chart-topping pop diva kicked off a press conference in New Orleans ahead of Sunday’s American football event by singing “The Star-Spangled Banner” a cappella after asking assembled reporters: “Would you guys mind standing?” Fielding questions afterwards, she declared: