A 'secret' witness could be brought to court to cast doubt on troubled singer Britney Spears' ability to look after her children.Reports in the US suggest ex-husband Kevin Federline's lawyer Gloria Allred is planning to bring the witness to court to reveal some "explosive" inside information about the star.The reports suggest the witness is a man who has already had his testimony accepted by the judge.Britney and K-Fed have been locked in a bitter custody battle for their two children Sean Preston and Jayden James since they split last year.On Friday, lawyer Laura Wasser filed a motion asking the LA court to make permanent a conditional July 30 order to make all documents dealing with custody, private.It was filed in response to a motion by a magazine and TV station to release some of the papers surrounding Britney's case.Meanwhile, rumours Britney would apologise for her her disastrous MTV performance at Sunday night's Emmy awards proved to be unfounded.© Independent Television News Limited 2007. All rights reserved.