ghost effect - practice footage

this is the effect i tend to use in my final music video. i'm going to film the singer in the playground. he's going to be a ghost, a passing memory. the way i did this was i filmed the background with a static camera, i then had my actor come in the shot. then i uploaded the footage into after effects and made the opacity about 50% for the actor. they had to be 2 seperate layers. it wasn't as difficult as i imagined. using this is my video shouldn't be a problem.