We’ve still an episode or so before Flash and Supergirl cross universes for a musical “Duet,” but why wait for the dress rehearsal? Our first footage has arrived, featuring Melissa Benoist and Grant Gustin in their Sunday best.

In addition to debuting first looks at Teri Hatcher an Kevin Sorbo in character, Monday’s Supergirl also brought with it the first formal “Duet” footage, featuring the two CW stars outfitted for the “alternate reality” wrought by Darren Criss’ Music Meister. We also get a brief look at Iris, but only a few other Super-stars just yet.

So reads the synopsis for both March 20 Supergirl episode “Star-Crossed,” marking Darren Criss’ Music Meister’s first appearance:

TERI HATCHER (“DESPERATE HOUSEWIVES,” “LOIS & CLARK: THE NEW ADVENTURES OF SUPERMAN”) AND KEVIN SORBO (“HERCULES”) GUEST STAR; DARREN CRISS (“GLEE”) MAKES HIS DEBUT AS THE MUSIC MEISTER

A new villain (guest star Teri Hatcher) comes to National City, putting Supergirl (Melissa Benoist) on high alert. Meanwhile, Winn’s (Jeremy Jordan) girlfriend, Lyra (guest star Tamzin Merchant), gets Winn in trouble with the law. Maggie (guest star Floriana Lima) attempts to help Winn but old loyalties get in the way. The Music Meister (Darren Criss) attacks Supergirl.

Along with March 21 Flash episode “Duet,” which explains the full musical premise:

DARREN CRISS (“GLEE”) GUEST STARS AS THE MUSIC MEISTER IN THE FLASH AND SUPERGIRL MUSICAL CROSSOVER

Barry (Grant Gustin) and team are surprised when Mon- El (guest star Chris Wood) and Hank Henshaw (guest star David Harewood) arrive on their Earth carrying a comatose Supergirl (guest star Melissa Benoist) who was whammied by the Music Meister (guest star Darren Criss). Unable to wake her up, they turn to Team Flash to save her. However, the Music Meister surprises The Flash and puts him in a similar coma, one that Team Flash can’t cure. Kara and Barry wake up without their powers in an alternate reality where life is like a musical and the only way to escape is by following the script, complete with singing and dancing, to the end.

The two-part event will feature Glee alum Darren Criss as the Music Meister, the first look at which you can see right here. Also lending their voices will be Jesse L. Martin, Carlos Valdes and Jeremy Jordan, along with Legends of Tomorrow stars Victor Garber and John Barrowman. Supergirl cast David Harewood and Chris Wood will also appear in non-singing roles, while original songs have been provided by both Crazy Ex-Girlfriend star Rachel Bloom, and the Golden Globe-winning La La Land lyricists Benj Pasek and Justin Paul.

You can get a good sense of the whole cast’s musical prowess here, but stay tuned for more footage of Flash and Supergirl’s musical team-up.

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