Attach shower to roman tub

I have a Roman Tub at my home and want to attach a shower to it. My plan was to find an adaptor that could attach to the roman tub faucet and connect with a shower diverter, attach and mount handheld shower to the wall. I haven’t had any luck finding an adaptor at Home Depot or via research online.

It makes me think either this is impossible (which is hard to believe – there must be a hacky solution to it haha) OR I’m looking at this the wrong way. I’ll be meeting w/plumbers next week.

I’ve attached a few images too. What would the best option be?

Please advise!