pbr Charlie Sheen has gone to extreme lengths to prove he is drug-free, claiming he has "nothing to hide".br ppbr The 45-year-old has taken a drugs test on camera for an American celebrity website.br ppbr The actor invited a crew from showbiz site RadarOnline.com into his Los Angeles mansion where he tested negative for marijuana, cocaine, opiates and methamphetamine.br ppbr It took place after a judge ordered Sheen's two young sons to be removed from his home after his ex-wife obtained a restraining order.br ppbr It is the latest twist in the drama surrounding the Two And A Half Men star.br ppbr Last week the show was cancelled for the rest of the series.