The Flash and Supergirl Musical Crossover: Villain, Release Date, Cast

Darren Criss will be playing Music Meister in The Flash/Supergirl musical crossover episode "Duet."According to Comicbook.com, The Glee alum will join former Glee co-stars The Flash's Grant Gustin and Supergirl's Melissa Benoist, who both broke onto the TV scene on the Fox musical dramedy.

Criss will play the villain of the musical crossover: The Music Meister. The Music Meister is a villain created for Batman: The Brave and the Bold who has the power to hypnotize people into a trance. Once in a trance, Music Meister has the power to make these people do whatever he wishes. 

A self-proclaimed nerd, Criss rose to fame in A Very Potter Musical before moving onto other projects like Glee and on Broadway in How to Succeed in Business Without Really Trying and Hedwig and the Angry Inch. It will be a lot of fun to see him reunited with Gustin and Benoist. This is great casting.

The Flash/Supergirl Musical Crossover Director

This isn't the first time we've heard the Music Meister's name mentioned in connection with this episode. Back in August, That Hashtag Show reported that he would be the baddie. At the time, they also mentioned that Joss Whedon was under consideration to direct the episodes, but there has been no additional confirmation on that. But since they got this part right, could they have the other thing right, as well?

But the villain has a lot in common with the villain in Joss Whedon's first musical TV episode: Buffy the Vampire Slayer's "Once More With Feeling," in which the villainous Sweet compels the people of Sunnydale to sing, dance, and reveal their hidden feelings. Could Music Meister do something similar? What good is a musical if characters aren't expressing themselves through song?

Of course, Whedon's involvement remains only a rumor at this point, given that The CW has yet to confirm or deny anything. However, That Hashtag Show has been breaking some big news recently (such as Finn Jones' casting as Marvel's Iron Fist), so — on the scale from rumor to real — it comes with some weight.

The Flash/Supergirl Crossover Musical Release Date

Now, we have an official date and title for the Supergirl/The Flash crossover (via Entertainment Weekly): March 20th and 21st. The musical will kick off at the end of Supergirl's March 20th episode before mostly taking place during The Flash's March 21st episode. The Flash episode will be called "Duet."

The Flash/Supergirl Crossover Musical Performances

We also know who will get musical performances in the episode: Grant Gustin, Melissa Benoist, Jesse L. Martin, Carlos Valdes, and Jeremy Jordan. Legends of Tomorrow star Victor Garber and Arrow alum John Barrowman will also stop by for musical performances. Supergirl's David Harewood and Chris Wood will also make appearances, but, sadly, will not sing.

The Flash/Supergirl Crossover Cast

In honor of all of this wonderful news, please enjoy these videos of various members of the extremely talented Supergirl and The Flash casts singing. Soon, we will have even more...

This also seems like a good time that various members of The Flash cast — Jesse L. Martin, Carlos Valdes, and Rick Cosnett — did a gospel version of "Ballad of Serenity" from Whedon's short-lived Firefly TV show as a thank you for Whedon's "outstanding" contribution to their Kickstarter campaign for "The Letter Carrier."

Which pre-existing songs should be featured in the Supergirl/The Flash crossover? Share your suggestions in the comments below...