Years and years ago (1989) I saw a film on late night tv while on holiday in LA. It was about siamese twins seperated at birth, one good one evil, I remember a knife being hidden in a birthday cake, "help me" written in blood on a window and the evil twin killing the good twin's boyf and hiding him in a sofa bed. Was i so completely tired after a 16 hour delay and made this up?? I have checked on imdb until I am blue in the face with no luck! Can anyone help? Thanks.
I was thinking it was Dead Ringers with Jeremy Irons, directed by David Chronenberg, but I think that was about identical twins not separated conjoined twins.