The CW is taking full advantage of its superhero-heavy prime-time lineup this season. Riding high from the success of four-show DCEU crossover 'Invasion!,' the network is prepared for another crossover between Supergirl and The Flash. Kara Danvers and Barry Allen first crossed paths in Supergirl season 1, before the show moved from CBS to The CW.

Unlike the previous crossover, this one will take advantage of its musically gifted casts. The main storyline will take place during next week's episode of The Flash, titled 'Duet', which finds Kara (Melissa Benoist) and Barry (Grant Gustin) at the mercy of the menacing Music Meister (Darren Criss). Benoist, Gustin, and Criss all shared screen time on FOX's hit teen drama Glee.

The 'Duet' premiere is almost here, and as a result The CW is ramping up promotion for the exciting crossover. Today, the network unveiled two new TV spots for the crossover, one which teases the actual episode and another featuring Supergirl star Melissa Benoist urging fans to watch. You can check out the trailer above, and catch the behind-the-scenes promo below.

This is a fun peek at the upcoming episode, and it expertly encapsulates the episode synopsis for 'Duet'. We see Music Meister in action, as he forces Barry and Kara into an alternate movie musical reality and forces them to perform for him, lest he kill them (in the alternate reality and in real life). The sneak peek teases appearances by Jesse L. Martin (The Flash), Victor Garber (The FlashLegends of Tomorrow), and John Barrowman (Arrow). This longer promo also builds on last week's teaser.

This crossover episode is bound to be a treat, given its all-star cast, but it is kind of a shame to see the entire thing restricted to the classical Hollywood "movie musical" genre. It would be easier for fans to connect to the story if the Music Meister merely transported Kara and Barry to an alternate reality where they could only express themselves in song (a la the Scrubs and Buffy musical episodes). Thus, preexisting issues within the show could still be acknowledged, just with way more pizzazz. It looks like this episode may just be a one-off, which would be a shame, considering how Supergirl especially has been pretty light on the character and plot development this season.

No matter what, 'Duet' will be a joyous affair; it just might skimp on the grit that usually makes these characters so compelling. Whether this episode is riotous romp or a fatuous flop, it ain't over until the fat lady (or, in this case, super-toned alien woman) sings.

Next: The Flash’s Savitar Reveal Different From Past Villain Twists

Supergirl returns to The CW with 'Star-Crossed' on Monday, March 20 at 8 p.m. EST, followed by The Flash on Tuesday, March 21 in the same time slot with 'Duet'.

Source: The CW