Demi Lovato got the giggles after taking a tumble walking down some stairs on stage during her ‘Until You’re Mine’ performance on Saturday night (June 27) at Mann Music Center in Philadelphia. “I planned that,” Demi joked later during the performance. It’s not the first time the ‘Sonny with a Chance’ star has fell on stage, as she’s joked about on Twitter. Watch fan filmed footage via YouTube below.