When the curtains were about to open you realized that the guy was behind you so you told him to go sit with the rest of the band so he did

You then look at everyone and you sigh as you wait for the band to start playing but nobody did. That’s when you hear Santiago start playing so that’s when you started singing. In the middle of your song you point at Santiago and he comes down on the stage with you as he starts singing with you and playing the instrument at the same time