CBS has officially confirmed that Grant Gustin will play The Flash on an upcoming episode of Supergirl, due to air on March 28th, 2016. Here is the official statement from Berlanti and Kreisberg, on the matter:
“We are so incredibly excited to announce something that we have dreamed of happening since we starting making Supergirl. We want to thank Grant Gustin for making the time to come visit (on top of his already immense workload) and all of the folks at CBS, The CW, Warner Bros. and DC for working this out. It is our pleasure and hope to create an episode worthy of everyone’s enthusiasm and support.”
Supergirl has been a huge success for CBS with Melissa Benoist starring as Superman’s cousin, Kara Zor-El – everyday twenty-something Kara Danvers by day, newfound savior of National City by night (and day, when it’s necessary).
With the crossover idea now official, it is up to Gustin and Benoist’s screen charisma in their roles of Barry Allen and Kara Zor-El/Danvers to be big selling points for their respective DC superhero TV shows, so that makes the prospect of a Supergirl and The Flash crossover all the more appealing.