The Flash has super-speed and time-travel chops. Supergirl can fly and fry stuff with her eyes. But can these CW superheroes sing?

In “Duet,” the Tuesday, March 21, episode of “The Flash,” our incredibly speedy superhero and Supergirl fall under the sway of an enigmatic villain, the Music Meister, and fight back with songs on their lips and taps on their shoes. Some of the songs are standards, like “Moon River,” but others have been written specifically for the show by Rachel Bloom of “Crazy Ex-Girlfriend” (another CW show) and Benj Pasek and Justin Paul, who recently took home an Oscar for “La La Land” and have “Dear Evan Hansen” on Broadway.

This may seem like an unusual turn of events for the cape-wearing set, but Andrew Kreisberg, a creator of “The Flash,” disagrees.

“We have them fighting sentient gorillas the week before, so for us it’s not any crazier or sillier that they’re singing,” he said.