Grant Gustin has been killing it as The Flash for a few seasons now, and what better way to welcome Melissa Benoist's Supergirl into the TV superhero fold than by visiting her in National City? The actors are currently filming the much-rumored-about Flash/Supergirl crossover episode, and luckily for us, Gustin is documenting every fun second of it on Instagram. In a selfie of the two in their super alter egos' costumes, he wrote, "Those two emblems look pretty good together . . . ," and we have to agree. Gustin and Benoist previously starred on Glee together as Sebastian Smythe and Marley Rose, so here's hoping their chemistry will be extra palpable in their upcoming episode together. Keep reading to see all the photos!