Grant Gustin Shares Behind-the-Scenes from Supergirl Crossover

Because the only way to make Supergirl and The Flash stars Melissa Benoist and Grant Gustin cuter [...]

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Because the only way to make Supergirl and The Flash stars Melissa Benoist and Grant Gustin cuter is a puppy and high-fiving a child, well, that's exactly what Gustin has provided.

In an instagram post, Gustin wrote of the crossover, which airs Monday March 28, "On the set of the Supergirl/Flash crossover in a nutshell. Puppies, absurd high fives with Melissa Benoist, lots of coffee and meeting many many fans, including Fred Savage and his kids."

The Supergirl crossover episode, guest starring Grant Gustin as Barry Allen/The Flash, was the big question asked of Greg Berlanti, an EP on both shows, from almost the moment Supergirl started airing.

The Flash returns to The CW tonight at 8pm.