VIDEO : ?The Flash?-?Supergirl? Musical Crossover Adds Darren Criss as Villain

The CW is staging a ?Glee? reunion, after casting Darren Criss to play the villain Music Meister in the musical crossover episodes of ?The Flash? and ?Supergirl? in March. ?Duet? will feature singing performances from Arrowverse actors Grant Gustin, Melissa Benoist, Jesse L. Martin, and more. There?s no word yet if the musical numbers will be original songs or covers of existing music.