Flash and Supergirl Stars Reveal Favorite Moments From Musical Episode

After months of discussion, the musical crossover between "The Flash" and "Supergirl" has arrived, airing as tonight's "Flash" episode on The CW. CBR caught up with some of the episode's stars to find out their favorite moments from "Duet," which guest-starred Darren Criss as the musically villainous Music Meister.

For "The Flash" star Grant Gustin, he was excited about both of his numbers in the episode, but had a special place in his heart for "Runnin' Home to You," written by the duo of Benj Pasek and Justin Paul -- who just last month won an Academy Award for their song "City of Stars," from "La La Land."

"I felt very lucky to sing that song by Pasek and Paul, who are exploding right now in the scene of music writing," Gustin told CBR on the red carpet before Saturday's PaleyFest event in Hollywood, paying tribute to "The Flash," "Supergirl," "Arrow" and "DC's Legends of Tomorrow." "I knew them a little bit from college -- they came to the master class where I went, Elon University. Me and Benj, especially, stayed close-ish since then. It was really cool and special to get to sing that, and they clearly had done their homework on not only the show, but Barry and Iris' relationship, and just what the whole show has been. They knew where they were coming from, and they wrote a near-perfect song for that moment. I felt really lucky to sing it."

Melissa Benoist, who stars in the title role of "Supergirl," went a little more old-school with her pick -- her version of Henry Mancini's "Moon River," first performed by Audrey Hepburn in "Breakfast at Tiffany's" and inspiring many cover versions in the past 55 years.

"I'm such a fan of the American songbook, and classic songs, that, like, Judy Garland and Rosemary Clooney sang, so singing Moon River was a joy for me," Benoist said.

For Candice Patton, Iris West on "The Flash," her highlight wasn't a musical one, but simply the character change that came as a result of the episode's plot: Thanks to the Music Meister's machinations, The Flash and Supergirl are both in a shared, dream-like state that looks a whole lot like an old-timey movie musical, providing the context for the songs along with altered versions of familiar characters. In the musical reality, Iris is a mobster's daughter, and most noticeably, much more freewheeling than we've typically seen her character over the past three seasons.

"She's had such a heavy past few seasons, of dealing with a lot of family and emotional issues," Patton told CBR. "It's nice playing a version of Iris that's a little carefree.

Given the backgrounds of both show's casts, a musical episode for "The Flash" and "Supergirl" feels like a natural choice. Gustin and Benoist were both on "Glee" along with other credits, Jesse L. Martin (Joe West on "The Flash") originated the role of Tom Collins on Broadway in "Rent" among many theater roles, Carlos Valdes (Cisco Ramon on "The Flash") played Andrej in the Broadway cast of "Once," and Jeremy Jordan (Winn on "Supergirl") has performed on Broadway and co-starred in the film version of "The Last Five Years." For the "Flash" creative team, while a musical episode was obviously a license to have some fun outside of the show's normal, superheroic parameters, it still adhered to the tenets of what makes the DC Comics-based show a success.

"It still followed our mantra of 'heart, humor, spectacle,'" "The Flash" executive producer Aaron Helbing told CBR. "Heart is going to an emotional story with Barry, Kara; with Iris and Mon-El, and their relationship. Humor, because we still always try to pepper in as much fun as we can. And spectacle -- when you go into a 1940s, 1950s-type world, and you get to see Joe West, and Malcolm Merlyn, Professor Stein, and all of these different characters, it just gives it a certain flavor and excitement. It's a time period we really fell in love with."

"The Flash" airs Tuesdays at 8 p.m. on The CW; "Supergirl" airs 8 p.m. on Mondays on The CW.

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