A guy on YouTube claims he set up a hidden camera in his apartment to find out why his food was going missing, and discovered a girl living in the roof space above his kitchen. She apparently emerged to raid his fridge, lounge around in his armchair and take advantage of his cable subscription.
The man who shot the video now says he is a professional actor called Joe Cummings. I'm thinking he got found out and decided he would stick to his basic story, but had more to lose by not fessing up to his identity.
The story is far-fetched, and the telltale clue is from about the 0:20 mark in the video: said feral intruder can clearly be seen waiting to emerge in the background. Even if the story wasn't a pile of BS, she would certainly have seen the camera being set up and known she was rumbled.
Besides, the barebones plot of this hoax is the basis of numerous urban legends (though usually it turns out to be Mexican immigrants hiding out in the attic). If this were real, the mainstream media would have picked it up by now.