CORRECTION:
This original post by me was incorrect. A little more research shows that the program *was* shot on film, so it could've been transferred to HD. It is possible that the production was "finished" on videotape and that the special effects were produced on videotape. If this is the case, the original film elements could be transferred to HD, but the special effects would have to be recreated for High Definition.
However, it was one of the most expensive television movies produced up until that time and Whitney Houston had expectations that it would be released theatrically. If, at some point, a theatrical release was anticipated, then all of the work would've been completed for film and not videotape. I guess only Disney really knows at this point...
Updated On: 2/13/21 at 11:00 PM