how do you add drywall to an opening in the ceiling with no existing frame?

I recently purchased a townhome. I am adding recess lighting in the kitchen and removed the old fluorescent lighting as well as the metal frame and plastic sheet shield. I am left with approx 4' x 6' recessed box with no way of attaching 1/2" drywall. Will it be ok to build a frame attach to the beams on the edges of the box then attach drywall.