Award-winning songwriters Benj Pasek and Justin Paul (La La Land, Dear Evan Hansen) have written a song for The Flash/Supergirl upcoming musical crossover episode. The Flash star Grant Gustin will perform the original song “Runnin’ Home To You” in the episode titled “Duet” airing Tuesday, March 21 at 8 PM on the CW.

In addition to “Runnin’ Home to You,” the episode will feature another original song penned by Crazy Ex-Girlfriend star and executive producer Rachel Bloom and Tom Root, entitled “Superfriends.”

Pasek and are the Oscar/Tony/Emmy-nominated songwriting team behind the Broadway musicals Dear Evan Hansen, A Christmas Story, The Musical and Dogfight. The duo penned the lyrics for the award-winning song “City of Stars” from La La Land, which was awarded a Golden Globe for Best Original Song, a Critics’ Choice Award for Best Original Song and a Los Angeles Film Critics Association Award for Best Music. Pasek and Paul have also received two Oscar nominations, one for “City of Stars” and a second for “Audition (The Fools Who Dream),” both from La La Land. Feature film credits include Trolls, The Greatest Showman and Medusa. Their songs have also been featured on Smash, Sesame Street and Johnny and the Sprites.

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“Benj and Justin are the premiere song-writing duo of our time,” said Andrew Kreisberg, Executive Producer for The Flash and Supergirl. “Not only are they two of the most talented people Greg and I have ever met, they are also two of the nicest. To have them be a part of our musical episode is beyond our wildest expectations. We hope everyone falls in love with the song they wrote for us as much as we did.”

Based on the characters from DC Comics, The Flash is produced by Bonanza Productions Inc. in association with Berlanti Productions and Warner Bros. Television, with executive producers Greg Berlanti, Andrew Kreisberg, David Nutter, Sarah Schechter, Aaron Helbing and Todd Helbing.