I don't know if it's the same as what you mean, but I have an imaginary world in my head and live in it constantly. I don't get a lot of things done, like cleaning the house, going shopping, getting ready for work, because I'm lying in bed living this different life in my head. And I have pictures of people I look at while I'm in my world, and they are characters that become real. I will get so in depth with these thoughts that I will get full emotions as if it were real life.

It's something I've done since I was a child. I remember having books and things and there would be a picture-whether a cartoon or a real person- who I would feel a connection to (it could just be the way they looked for example), and I would leave this picture in front of me while I did things because it was like they were there watching me. Then it progressed into a complete fantasy world. In fact it's probably more real to me than reality.
Over the years the characters or story line of my fantasy worlds change, but they generally have always revolved around a male figure, first it started as someone who was a father, now it's progressed into a male my imaginary self will be in a relationship with. But other than my first name, my character is a different person with an almost completely different life.
So I tend to become so wrapped up with what's in my mind that I will find myself talking out loud, or silently to myself, even in public. Unless I am so busy I literally don't have time for it, such as while I'm at work or on campus studying, all I am doing in living in my other world talking to myself like a complete lunatic.