The CW has been hyping the musical crossover episode between “The Flash” and “Supergirl” for awhile now.

But they have finally released a teaser trailer for the new crossover called “Duet.” And it won’t just be between “The Flash” and “Supergirl.” “The Legends of Tomorrow” cast will also be making an appearance.

Comicbook.com reports that Grant Gustin (Barry Allen, The Flash) Jesse L. Martin (Detective Joe West), Carlos Valdes (Cisco Ramon, Vibe), Melissa Benoist (Kara Danvers, Supergirl), Jeremy Jordan (Winn Schott), John Barrowman (Malcolm Merlyn), and Victor Garber (Martin Stein) will all be singing.

It’s no surprise that Jesse L. Martin made the list. His Earth-2 version was a hit club singer at Jitterbugs.

Here’s a refresher in case you forgot from The Flash Season 2:

The song will reportedly be written by Rachel Bloom and the recent Oscar-winning duo of La La Land.

Here’s the full synopsis of the episode from The CW:

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.

Dermott Downs directed the episode with story by Greg Berlanti & Andrew Kreisberg and teleplay by Aaron Helbing & Todd Helbing (#317). Original airdate 3/21/2017.