It has not escaped notice for many fans of the Arrowverse that a number of the actors cast in the various shows have a history with musicals. Colin Donnell, John Barrowman, Jesse L. Martin, Carlos Valdes, Victor Garber, Arthur Darvill, Ciara Renee, and Jeremy Jordan have all starred in Broadway musicals. Supergirl and The Flash actors Melissa Benoist and Grant Gustin both were on the musical show Glee, and Jeremy Jordan and Jesse L. Martin were also on a musical series, Smash – along with Broadway star Andy Mientus who has appeared on The Flash as The Pied Piper. It seemed like only a matter of time before a musical episode happened – and now the wait is almost over.

On the March 20th episode of Supergirl, ‘Star-Crossed’, the crossover will kick off, and then most of the story will be told in The Flash episode ‘Duet’. It also is technically a bit of a crossover with Legends of Tomorrow, with Victor Garber returning to The Flash to participate. As will John Barrowman, who signed one of several contracts which lets him move between all the Arrowverse shows though he has mostly been seen on Legends of Tomorrow.

DC All Access has now released a video from the set of ‘Duet’ where they talked to several of the participating actors and learned a few things about the musical. Possibly the most telling hint came from Darren Criss, who is playing the episode’s guest villain, the Music Meister. It’s quite the reunion for Criss – also a Broadway alum – who was on Glee with Benoist and Gustin and went to college with Valdes, and he revealed a bit of what his character is up to:

“So the Music Meister has plans for them, he’s kind of stringing all of the main character along. Particularly the couples, to maybe teach them a lesson? That’s what he says.”

The Flash Supergirl Duet Barry Allen Kara Danvers Supergirl/Flash Musical Crossover Video Offers New Story Details

Speaking of couples, Candice Patton spoke about how she will be involved, as the daughter of a gangster and not Iris. That fits in well with what was already revealed, the Music Meister traps Barry and Kara in a fantasy world where the people they know are there, but not as themselves. Since Martin is playing a gangster, it sounds like Patton is still his onscreen daughter in this fantasy, even if they are not specifically Joe and Iris West.

Gustin and Benoist also spoke a bit about the duet they are singing in ‘Duet’. While they did not use the song’s name, it has previously been announced that they are singing a song called “Superfriends” which is co-written by Crazy Ex-Girlfriend‘s Rachel Bloom. Gustin called it “a fun, comedy song” and mentioned that there was a lot of space within it to improvise.

With the sheer amount of singing and dancing talent in the cast, ‘Duet’ is poised to be an amazing treat for fans of Supergirl and The Flash.

Supergirl continues Monday, March 20 with ‘Star-Crossed’ at 8pm on The CW. The Flash Tuesday, March 14 with ‘Into the Speed Force’ at 8pm on The CW, with ‘Duet’ at the same time on March 21.

Supergirl/Flash Musical Crossover Video Offers New Story Details