grammar - Is this construction correct? "Today is [(pro)noun] [gerund]"

"Today is [(pro)noun] [gerund]"

Context: Some time ago, my friend and I were messaging each other and then I used this construction. He immediately said that my sentence should've been "Today [(pro)noun] is [present participle]". I replied saying that that construction changes the meaning I originally intended. I said that "Today" should be the subject, not the adverb. Then there was a back and forth of arguments. I then made up an instance in restaurant where there will be a guest singer. A manager says "Today is Madonna singing". That didn't work either. I then told him to think of it like a list (yesterday was x x-ing, today is x x-ing, tomorrow will be x x-ing). I told him to also think of "Madonna singing" as a noun phrase, not noun + verb. He asked some of his friends too and none of them have heard of this construction.

So, is this construction something that exists or is it something I made up? I don't think I made it up because I have a definite feeling I picked it up from somewhere and I have kept it because I think it's correct.

Edit 1: Another example I thought of is "Tomorrow will be him doing it" (which seems correct to me).

Edit 2: Thanks to everyone that answered! (I am not going to put the tick mark on anyone because many people helped; putting it on only one person would be unfair).