Turning small 2 ft wide bedroom closet into double closet?

Ok so i think that this may get me a little over my head but wanted to see if anyone on here has done this or had any advice on it. My daughters bedroom is very small and has one very small 2 1/2 ft wide and about 2-3 ft deep closet in her room however there is 4 ft worth of unused wall space right beside it. So theoretically couldnt i knock out about 3 ft of that space and it be empty use-able space for me to build in bookshelves and built in drawers at bottom? Or would i open this wall and find a nightmare? there is no electrical outlets or anything on that wall, so wouldnt you find un supportive wall studs that could be removed then just drywall and create the built ins?