This isn't the most interesting bit of news now, however.
According to a report from YouTube channel That Hashtag Show, the CW has turned to Joss Whedon himself to direct the musical crossover.
This is crazy cool on a couple of different levels. First is the obvious fact that Joss Whedon was once one of the key architects of the Marvel Cinematic Universe. While the Arrow-verse is no DC Extended Universe, this bit of news would solidify Whedon taking the leap from one comic book giant to the other.