Macross Plus, which is about a pop star who is entirely a computer program that sings, but who has fans as devoted as any present-day pop star. Anime being anime, there was of course a whole plot line about her AI going rogue (plus giant robots of course), but I remember thinking "how weird, a pop star who doesn't exactly exist". Well, technology progresses, and sure enough, we have one now.
Years ago I came across an example of a speech synthesis system that could produce song as well as speech. Not exactly natural-sounding, but a relatively straightforward modification of speech synthesis tools. Being an open-source research tool, it had the usual idiosyncratic, arcane, and mostly undocumented scripting-language interface I've come to expect, and it didn't make much of a splash.
Recently, though, the technology has been commercialized. A Japanese company took this song-synthesis technique and built it into a software synthesizer you can run on your PC. This would have placed it alongside such things as FruityLoops and Rebirth. But that's not all they did.
Reasoning, I guess, that singers are often more than just one more musician in a band, they're the visible face and personality of the band, they decided that these song synthesis systems needed faces. So for each package of recorded voice samples, each "voice", they created a character. Often these are based on the artist whose voice samples went into the recording; for example the "Megpoid" voice pack is voiced by Megumi Nakajima, and the character has green hair and goggles as a reference to the character Ranka Lee that Nakajima voiced in a later Macross series.
I can certainly understand a song synthesizer as a musical tool, in the same way as a drum machine or traditional synthesizer, and I think it'll be interesting to see what little garage bands do with them. I can also see that voice packs carry a lot more personality than sample packs for other software musical instruments. But I still find the creation of a virtual character a bit weird. Will they develop fan clubs and largely fictional tabloid soap-opera histories in the way that actual famous singers do?