|Not performing IN a bar but ON the bar top!|
Once you have green screen footage - especially if it incorporates full body movement (as opposed to the maximum MLS dictated by using a single sheet unless you're very careful) - you have incredible creative freedom over how you use it.
LAYERING - which isn't always through green screened footage - is one of the fundamentals of music video, a very common device but not one seen much in TV drama for example.
I'd welcome your suggestions (as blog comments) on useful examples to add to this post from your own knowledge/research.
Here's a simple example from a Thai dance-pop artist.