'The Flash' - 'Supergirl' musical crossover cast, premiere dates revealed

"The Flash"-"Supergirl" crossover episodes will air in March, The CW announced Friday.

While the vast majority of the action will take place on "The Flash" in an episode fitting entitled "Duet," the story will be set up at the end of the "Supergirl" episode preceding it the day before – much like with this year's four-show crossover.

"Supergirl" will air Monday, March 20, followed by "The Flash" on Tuesday, March 21.

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"Duet" will be directed by Dermott Downs and will feature singing performances from Arrowverse actors Grant Gustin (Barry Allen/The Flash), Melissa Benoist (Kara Zor-El/Supergirl), Jesse L. Martin (Joe West), Victor Garber (Dr. Stein/Heatwave), Carlos Valdes (Cisco Ramirez/Vibe), Jeremy Jordan (Winn Scott), and John Barrowman (Malcolm Meryln), while also including non-singing guest star appearances from David Harewood (Hank/Martian Manhunter) and Chris Wood (Mon-El).

There's no word yet if the musical numbers will be original songs or covers of existing music.

Also Read:Black Flash Is Coming to CW's 'Arrow'-'The Flash' Universe This Season

Both "The Flash" and "Supergirl" were recently renewed for new seasons by The CW for seasons 4 and 3, respectively.

"Supergirl" airs Mondays at 8 p.m. ET on The CW and "The Flash" airs Tuesdays at 8 p.m.

Read original story 'The Flash'-'Supergirl' Musical Crossover Cast, Premiere Dates Revealed At TheWrap