'The Flash' & 'Supergirl' To Join Forces For Two-Part Musical Crossover

The Flash and Supergirl are set to reunite their cast members through another pair of crossover episodes, this time with a musical theme.

As EW reports, executive producer Greg Berlanti told the Television Critics' Association press tour that these episodes would be in addition to the already announced four-way crossover between The Flash, Supergirl and The CW's other live-action DC Comics shows, Arrow and Legends Of Tomorrow — that's set to air in December — and would likely appear in the latter stage of the season, using "mostly pre-existing songs".

"There's going to be a musical pair of episodes in the back half of the year between Supergirl and The Flash," Berlanti told the TCA, explaining his own love of musicals and referring to the strong singing chops of many of his stars, including the series' principals, Grant Gustin and Melissa Benoist, who both have history on Glee.

"I’ve probably been leading the charge myself just because my own nexus of loving musicals and loving superheroes," he continued. "So many times it’s a musical episode off the set, and I think on all the shows, we love to use all of the character talents as much as possible.

"We've toyed with who potentially the villain could kind of be. My sense is we’ll be very careful about how it is they kind of break into song and there will probably be an element of being in some character’s head at the time."

If Berlanti is really stuck for inspiration on the villain front, he could always ask Neil Patrick Harris to reprise his role as the Music Meister (from Batman: The Brave & The Bold), whose only real crimes were offences against fashion, and also a lot of theft. He'd certainly help its chances of being added to our list of greatest TV musical episodes, at any rate.

The revelation comes a few days after the news broke that Fox comedies Brooklyn Nine-Nine and New Girl would be crossing over in their upcoming seasons. 

The Flash and Supergirl first crossed over last season (The Flash's second and Supergirl's first), while the latter was still on its previous network home of CBS.