The Flash and Supergirl are going to Old Hollywood in the first trailer for their upcoming musical crossover.

When the villainous Music Meister (Darren Criss) puts Kara (Melissa Benoist) in a coma at the end of Supergirl (Monday, March 20 at 8/7c), her friends travel to Central City to seek help stopping the villain — and saving Kara — the following night, on The Flash (Tuesday, March 21 at 8/7c).

However, Music Meister gains the upper hand when he puts Barry (Grant Gustin) in a coma that even Team Flash can't save him from. As it turns out, the superhero duo is actually stranded in an alternate musical reality without their powers, and the only way Kara and Barry can only escape is if they follow Music Meister's script!

That's why in the 10-second teaser, Barry and Kara are decked out in their Old Hollywood best instead of their super-suits, and are showing off their fancy footwork rather than their crime-fighting capabilities. But Barry and Kara won't be the only ones showing off their singing skills in the episode: Joe (Jesse L. Martin), Dr. Stein (Victor Garber), Malcolm Merlyn (John Barrowman), Cisco (Carlos Valdes) and Winn (Jeremy Jordan) will also belt out tunes.