Hi guys. I've been searching for a while on how to solve this problem and could use a hand.
About 7 years ago I installed a 6' Jacuzzi tub with a Moen Roman tub faucet on the outside corner (on the drain side of the tub). It's been fine for us, but now it's time to sell the house and people are complaining that there isn't a shower in that bathroom. I'd like to be able to add a simple shower and prefer not to use a hand shower. I dont' think that's what people are looking for. Currently there is only two rows of tile above the tub, but I have enough to make a nice enclosure. (Now my wife gets why I don't throw out good materials!

Would it be ok to tee in before the Roman faucet and then run a "shower only" kit up the wall? I can access the water lines before they go into the faucet, and roughing in the shower piping won't be too tough. I'm not concerned about taking out tile and sheetrock, that part's pretty simple. I just want to make sure what I'm thinking here is ok to do and won't cause problems down the line.
I can supply pictures if that would help.

Thanks in advance.