Toxic wild girl Britney Spears has been digitally altered to look slimmer in her new video.The 26-year-old singer appears more toned and trim in the final promo for her latest single Piece of Me, in stark contrast to a leaked unedited version of the video which appeared on the Internet earlier this month.The promo, which cost around $500. thousand, features Britney and a group of look-a-likes evading the paparazzi by wearing matching wigs and storming a Hollywood club.Despite having gained some weight since her chart-topping glory days, director Wayne Isham insists Britney was as "beautiful" as ever on set.He said: "On set she was very professional, excited to work and beautiful as always. I was impressed with her focus as she choreographed the dance herself. Her endurance was remarkable, as we had a long day."Wayne, who also directed Britney's I'm Not a Girl, Not Yet a Woman video, added the star's stamina was "amazing".He said: "She almost outlasted me, which is amazing! It was a pleasure to work with her again."