Britney Spears upset dancers and the crew on the set of her "Pieces of Me" video by showing up 12 hours late to the shoot Tuesday at LA restaurant and nightclub Social Hollywood. Despite an 8 a.m. call time, Spears didn't leave her Beverly Hills home until after 7 p.m. after Kevin Federline's bodyguards picked up sons Sean Preston and Jayden James. She arrived on set around 8:35 p.m. "I've been there since 3 p.m. and have not shot a thing!" one dancer told Us mag. "I finally finagled my way out. It's all very unorganized. They are calling in more people for late night." In the video, Spears and four lookalikes - dress in black newsboy caps, sunglasses, black trench coats and short blonde wigs - try to trick the paparazzi. Spears used a "body double to shoot all the scenes that don't require her face," according to an on-set source. The shoot wrapped just after 5 a.m.