Barry Allen is racing to National City! "The Flash" star Grant Gustin will crossover to "Supergirl" with Melissa Benoist on an episode to be broadcast on Monday, Mar. 28, on CBS. As of now, no specific details are known about what will draw the Scarlett Speedster across networks, but the executive producers are just as pumped up about it as the fans.

"We are so incredibly excited to announce something that we have dreamed of happening since we started making 'Supergirl' - 'The Flash' and 'Supergirl' are teaming up!" executive producers Greg Berlanti and Andrew Kreisberg said in a joint press release. "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. And finally, thanks to the fans and journalists who have kept asking for this to happen. It is our pleasure and hope to create an episode worthy of everyone's enthusiasm and support."

Initially, Berlanti and Co. were reluctant to cross over their superhero stars given the expanding complexity of the shared universe The CW was building with "Arrow," "The Flash" and "DC's Legends of Tomorrow." However, "Supergirl's" ratings have been a bit up and down through its initial run, so securing an appearance from the established and popular Flash character should give the show a nice little boost.

Will the two heroes be going head-to-head, or will they be joining forces to defeat a common enemy? Will any sparks fly between the two? We'll just have to wait to find out.

Gustin will pop up on CBS' "Supergirl" on Monday, March 28.