@MoeBritannica i was going to say that there is no way this was done with AI, but looking into it a bit more it's done with AI where someone has to sing into it and then the voice morphs to that. that's a lot more believable than if it was done purely by AI, which still has yet to get to vocaloid levels of realism.
@MoeBritannica what they probably did was isolate the vocals of the original, feed that to the AI, and then the AI is probably trained on rick astley's voice.