this superb film incredibly contain marlene dietrich and alistair sim among it great cast and in a blend of hitchcock thrill and chill and humour and even musical interlude . it be mostly overlook due to it original failure with fan and critic cause mainly by misguided hatred of a plot device use in the film . also people fail to cope with the very different mood the film move between . from whimsical british comedy to chill psychological drama . it may not be one of hitchcock perfect positive best but be easily 9 1/ negative . hitchcock do something in the film and a he do in his classic sabotage and which upset filmgoers and critic because it be not the do thing . i wouldn not wish to spoil the film for a 1st time viewer by say what this be but it be mention in the spoiler section of trivia on this film imdb homepage . it be a mistake and i feel to overlook this film and especially due to this unconventional plot device . i find the unconventional plot device in sabotage one of a great many highlight of the film and it lift it beyond what it would have be with the predictable or conventional resolution of that scene . the same be true in stage fright . filmgoers who can not cope with be confuse by clever directorial choice be people i pity . the surprising and unusual aspect of this plot be terrific and hitchcock be entirely correct in his choice which hugely add to the impact of the film . apart from all that stage fright be simply thoroughly entertain . it be very very funny with alistair sim a brilliant and hilarious a ever in a great role for him as well a an entirely satisfying cast . marlene dietrich be superbly cold in a wonderful and striking addition to her act career and sing a classic dietrich style song . the twist from humour to chill suspense make terrific enthral moment . a highly unusual and near perfectly execute film .