In the music video the singer(male) is playing a guitar that really is a girl. What song is it?

So I remember really liking this song but I don't remember how it
goes. I don't remember who the singer was but I remember that in the
music video he was playing a guitar/girl.. So this girl had strings on
her back or something and he was playing them. What's the name of the
song and the singer/band?
Thanks so much :)