American Idol judge Simon Cowell is struggling to keep his opinions to himself on his new US show AMERICA'S GOT TALENT. The British music mogul has a clause in his Idol contract which bans him from taking on his Mr Nasty persona on any other US TV show. Cowell, who produces America's Got Talent, has to stay quietly behind the scenes and silently watch British journalist PIERS MORGAN, R+B singer Brandy Norwood and former Baywatch star David Hasselhoff tell wannabe stars what they think of their 'talents'. Cowell tells the New York Post, "It's been very tempting. There have been times when I've watched the show and thought to myself, 'God I wish I was judging this.' "But I've got to keep my mouth shut."