There were thousands of empty seats at the Pavilhao Atlantico arena in Lisbon, Portugal, as Jennifer Lopez put on a show for free – but it was just a rehearsal for her tour. The singer, who performs at the venue on Friday night as part of her Dance Again world tour, decided to open her practice run to the public, announcing on her website that 1,500 fans could use their concert tickets to claim a spot for the performance. Despite the free offer, up until the time of the start there were members of her crew clutching large amounts of tickets to give away to passers by outside. Inside, however, the fans seemed to love the opportunity for a more personal performance and even after a huge delay they gave the Puerto Rican a warm reception.