I was wondering how in the world they got ChatGPT to do this, but it's actually interesting:

  "Got ChatGPT to write some midi music ... used another ChatGPT prompt to create the computer generated voice in python and compiled the track." 

  "ChatGPT told me to write a MusicXML file that I uploaded to https://www.sinsy.jp/ ... Sinsy is an HMM/DNN-based singing voice synthesis system. You can generate a singing voice sample by uploading the musical score (MusicXML) to this website."

WAV files for both attached in the original post.

Btw there is a lot of AI that creates "audio" - voiceovers, background music, etc. So you don't need to use ChatGPT for this, but still interesting it can produce MIDI and MusicXML files from it.