Leighton Meester started the filming of Gossip Girl: Season 5 with French actress Roxanne Mesquida, on a very hot day in New York, NY on July 7th, 2011. After scenes of her running in high heels in the heat, she gave her feet a rest in flip flops after which she chowed down on a pretzel with mustard. Source Uploaded Picture:? PHOTO GALLERY: