Surpise dinner idea help please?

Hello all I have been with my bf for a year now. Our relationship is going good. He always there for me. He seen me sweet text message at night he take care of me when I'm sick. I want to do something really special for him so I made reservation for a upscale resturant so can just talk. What should I tell him when I get there and what do I wear I don't want to over dress thanks