The Japanese have succeeded in making the predictions of William Gibson and Howard Tayler (some 4 years afterwards) come true.
We now have a holographic pop idol. She looks real enough to the people who bought tickets for the show. She looks real enough to me. And, indeed, this is a live performance.
How do they do it? Well -- there's a bit of magic there, but my gut instinct is that it's similar to an old Victorian stage trick involving a somewhat transparent mirror at an angle to a sheet of glass. It's commonly called Pepper's ghost.
Still -- that's not the most interesting bit to me. The question is how real can they actually make her? My suspicion is that they could make her very real indeed -- seemingly as human as CGI will allow. Think of Avatar here.
I strongly suspect that it's related to an odd principle called the Uncanny Valley which was theorized by a Japanese roboticist who noticed that there was a point at which human analogues became real enough to creep people out. At this point, they're repellent and tend to evoke negative reactions.
In principle, there's a later point where things become still more real and can no longer distinguish them from human.
(Side note: "39's giving" is an odd phrasing. Three nine in Japanese can be pronounced as "san-kyuu" which is similar to "thank you" or "thank". I'm also told that it can also be pronounced as "Miku", so it may have been a pun.)