Should I get dressed up?

I have recently been thinking about how to spice up things in the bedroom with my Friends With Benefits. I feel like he isn't as excited about me as he use to be. I was thinking about going and buying some new lingerie, and wearing it under some of my normal clothes, so that when he takes them off he would be surprised. But I don't know if that's too far.... He is also my best friend in this whole world so I don't know if dressing up for him would be too much...