23 January 2013The on-screen bitchiness between them may be one of the highlights of the current series of Britain's Got Talent, but judging panel newcomer David Walliams may have hit a raw nerve by accusing music mogul Simon Cowell of having had cosmetic surgery. Cowell was clearly embarrassed by the remark, reported the Daily Mail, but it added that sightings of him while he filmed the last series of X Factor USA of him with a puffy-looking face had ignited rumours that the impresario had undergone a course of facial fillers.However, Cowell chose to fight back by deflecting attention away to his success with the show. "It doesn't matter whether people like me or not," he said. "I'm a good judge." But proving that the two panellists really are good buddies, Walliams was said to have followed a would-be contestant on the show performing a lap-dance for Cowell by staging a mock routine of his own for the show's mastermind.