What can I use to get this effect (link)?

It is just lighting. The light from the window on the right with the room being dark on the left. The lens was probably a fast lens because the face is in focus, but the cat in the front is blurred. No flash was used. It's a nice picture and the clothes make the 80's look. Really, is very easy to replicate with the right lens. I would also venture to say that it was cloudy outside or overcast. No sun light was evident.