Does anyone know of a VST or application that can create authentic sounding double track vocals? For cases where I have an original take, but I want the sound of double-tracked vocals when mixing after the session has ended and the artist has gone home?

I don't want "ADT", which I view as more of an effect. I'd like it to sound as much as possible like a second take from the same artist with some natural variation. I actually don't even care if it is AI, but realize that is banned here.