Ahead of The Flash's appearance in Supergirl, Grant Gustin ("Barry Allen/The Flash") has shared a photo alongside Melissa Benoist ("Kara Danvers/Supergirl") from the set of the upcoming crossover. Gustin posted the photo on Instagram, along with the caption: "Those two emblems look pretty good together." Gustin also humorously tweeted about the difference between filming The Flash in Vancouver (where the temperature is currently in the 40s and 50s fahrenheit) vs.