Jeffrey

The actor Bob Hoskins died recently.  While working of the mainly animated feature film Who Framed Roger Rabbit, he described a spell of hallucinations caused by him having to visualize the animated characters he was acting with in order to aline the sight-line of his eyes to the animations.

"I think I went a bit mad while working on that. Lost my mind. The voice of the rabbit was there just behind the camera all the time," he recalled. "The trouble was, I had learnt how to hallucinate. My daughter had an invisible friend called Jeffrey and I played with her and this invisible friend until one day I actually saw the friend."

http://edition.cnn.com/2014/04/30/showbiz/obit-bob-hoskins/index.html